| // Copyright 2012-2017 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| //! Unicode string slices. |
| //! |
| //! The `&str` type is one of the two main string types, the other being `String`. |
| //! Unlike its `String` counterpart, its contents are borrowed. |
| //! |
| //! # Basic Usage |
| //! |
| //! A basic string declaration of `&str` type: |
| //! |
| //! ``` |
| //! let hello_world = "Hello, World!"; |
| //! ``` |
| //! |
| //! Here we have declared a string literal, also known as a string slice. |
| //! String literals have a static lifetime, which means the string `hello_world` |
| //! is guaranteed to be valid for the duration of the entire program. |
| //! We can explicitly specify `hello_world`'s lifetime as well: |
| //! |
| //! ``` |
| //! let hello_world: &'static str = "Hello, world!"; |
| //! ``` |
| //! |
| //! *[See also the `str` primitive type](../../std/primitive.str.html).* |
| |
| #![stable(feature = "rust1", since = "1.0.0")] |
| |
| // Many of the usings in this module are only used in the test configuration. |
| // It's cleaner to just turn off the unused_imports warning than to fix them. |
| #![allow(unused_imports)] |
| |
| use core::fmt; |
| use core::str as core_str; |
| use core::str::pattern::Pattern; |
| use core::str::pattern::{Searcher, ReverseSearcher, DoubleEndedSearcher}; |
| use core::mem; |
| use core::ptr; |
| use core::iter::FusedIterator; |
| |
| use borrow::{Borrow, ToOwned}; |
| use boxed::Box; |
| use slice::{SliceConcatExt, SliceIndex}; |
| use string::String; |
| use vec::Vec; |
| use vec_deque::VecDeque; |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub use core::str::{FromStr, Utf8Error}; |
| #[allow(deprecated)] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub use core::str::{Lines, LinesAny}; |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub use core::str::{Split, RSplit}; |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub use core::str::{SplitN, RSplitN}; |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub use core::str::{SplitTerminator, RSplitTerminator}; |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub use core::str::{Matches, RMatches}; |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub use core::str::{MatchIndices, RMatchIndices}; |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub use core::str::{from_utf8, from_utf8_mut, Chars, CharIndices, Bytes}; |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub use core::str::{from_utf8_unchecked, from_utf8_unchecked_mut, ParseBoolError}; |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub use core::str::SplitWhitespace; |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub use core::str::pattern; |
| |
| |
| #[unstable(feature = "slice_concat_ext", |
| reason = "trait should not have to exist", |
| issue = "27747")] |
| impl<S: Borrow<str>> SliceConcatExt<str> for [S] { |
| type Output = String; |
| |
| fn concat(&self) -> String { |
| if self.is_empty() { |
| return String::new(); |
| } |
| |
| // `len` calculation may overflow but push_str will check boundaries |
| let len = self.iter().map(|s| s.borrow().len()).sum(); |
| let mut result = String::with_capacity(len); |
| |
| for s in self { |
| result.push_str(s.borrow()) |
| } |
| |
| result |
| } |
| |
| fn join(&self, sep: &str) -> String { |
| if self.is_empty() { |
| return String::new(); |
| } |
| |
| // concat is faster |
| if sep.is_empty() { |
| return self.concat(); |
| } |
| |
| // this is wrong without the guarantee that `self` is non-empty |
| // `len` calculation may overflow but push_str but will check boundaries |
| let len = sep.len() * (self.len() - 1) + |
| self.iter().map(|s| s.borrow().len()).sum::<usize>(); |
| let mut result = String::with_capacity(len); |
| let mut first = true; |
| |
| for s in self { |
| if first { |
| first = false; |
| } else { |
| result.push_str(sep); |
| } |
| result.push_str(s.borrow()); |
| } |
| result |
| } |
| |
| fn connect(&self, sep: &str) -> String { |
| self.join(sep) |
| } |
| } |
| |
| /// An iterator of [`u16`] over the string encoded as UTF-16. |
| /// |
| /// [`u16`]: ../../std/primitive.u16.html |
| /// |
| /// This struct is created by the [`encode_utf16`] method on [`str`]. |
| /// See its documentation for more. |
| /// |
| /// [`encode_utf16`]: ../../std/primitive.str.html#method.encode_utf16 |
| /// [`str`]: ../../std/primitive.str.html |
| #[derive(Clone)] |
| #[stable(feature = "encode_utf16", since = "1.8.0")] |
| pub struct EncodeUtf16<'a> { |
| chars: Chars<'a>, |
| extra: u16, |
| } |
| |
| #[stable(feature = "collection_debug", since = "1.17.0")] |
| impl<'a> fmt::Debug for EncodeUtf16<'a> { |
| fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| f.pad("EncodeUtf16 { .. }") |
| } |
| } |
| |
| #[stable(feature = "encode_utf16", since = "1.8.0")] |
| impl<'a> Iterator for EncodeUtf16<'a> { |
| type Item = u16; |
| |
| #[inline] |
| fn next(&mut self) -> Option<u16> { |
| if self.extra != 0 { |
| let tmp = self.extra; |
| self.extra = 0; |
| return Some(tmp); |
| } |
| |
| let mut buf = [0; 2]; |
| self.chars.next().map(|ch| { |
| let n = ch.encode_utf16(&mut buf).len(); |
| if n == 2 { |
| self.extra = buf[1]; |
| } |
| buf[0] |
| }) |
| } |
| |
| #[inline] |
| fn size_hint(&self) -> (usize, Option<usize>) { |
| let (low, high) = self.chars.size_hint(); |
| // every char gets either one u16 or two u16, |
| // so this iterator is between 1 or 2 times as |
| // long as the underlying iterator. |
| (low, high.and_then(|n| n.checked_mul(2))) |
| } |
| } |
| |
| #[stable(feature = "fused", since = "1.26.0")] |
| impl<'a> FusedIterator for EncodeUtf16<'a> {} |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Borrow<str> for String { |
| #[inline] |
| fn borrow(&self) -> &str { |
| &self[..] |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl ToOwned for str { |
| type Owned = String; |
| fn to_owned(&self) -> String { |
| unsafe { String::from_utf8_unchecked(self.as_bytes().to_owned()) } |
| } |
| |
| fn clone_into(&self, target: &mut String) { |
| let mut b = mem::replace(target, String::new()).into_bytes(); |
| self.as_bytes().clone_into(&mut b); |
| *target = unsafe { String::from_utf8_unchecked(b) } |
| } |
| } |
| |
| /// Methods for string slices. |
| #[lang = "str"] |
| #[cfg(not(test))] |
| impl str { |
| /// Returns the length of `self`. |
| /// |
| /// This length is in bytes, not [`char`]s or graphemes. In other words, |
| /// it may not be what a human considers the length of the string. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let len = "foo".len(); |
| /// assert_eq!(3, len); |
| /// |
| /// let len = "ƒoo".len(); // fancy f! |
| /// assert_eq!(4, len); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn len(&self) -> usize { |
| core_str::StrExt::len(self) |
| } |
| |
| /// Returns `true` if `self` has a length of zero bytes. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s = ""; |
| /// assert!(s.is_empty()); |
| /// |
| /// let s = "not empty"; |
| /// assert!(!s.is_empty()); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn is_empty(&self) -> bool { |
| core_str::StrExt::is_empty(self) |
| } |
| |
| /// Checks that `index`-th byte lies at the start and/or end of a |
| /// UTF-8 code point sequence. |
| /// |
| /// The start and end of the string (when `index == self.len()`) are |
| /// considered to be |
| /// boundaries. |
| /// |
| /// Returns `false` if `index` is greater than `self.len()`. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let s = "Löwe 老虎 Léopard"; |
| /// assert!(s.is_char_boundary(0)); |
| /// // start of `老` |
| /// assert!(s.is_char_boundary(6)); |
| /// assert!(s.is_char_boundary(s.len())); |
| /// |
| /// // second byte of `ö` |
| /// assert!(!s.is_char_boundary(2)); |
| /// |
| /// // third byte of `老` |
| /// assert!(!s.is_char_boundary(8)); |
| /// ``` |
| #[stable(feature = "is_char_boundary", since = "1.9.0")] |
| #[inline] |
| pub fn is_char_boundary(&self, index: usize) -> bool { |
| core_str::StrExt::is_char_boundary(self, index) |
| } |
| |
| /// Converts a string slice to a byte slice. To convert the byte slice back |
| /// into a string slice, use the [`str::from_utf8`] function. |
| /// |
| /// [`str::from_utf8`]: ./str/fn.from_utf8.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let bytes = "bors".as_bytes(); |
| /// assert_eq!(b"bors", bytes); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline(always)] |
| pub fn as_bytes(&self) -> &[u8] { |
| core_str::StrExt::as_bytes(self) |
| } |
| |
| /// Converts a mutable string slice to a mutable byte slice. To convert the |
| /// mutable byte slice back into a mutable string slice, use the |
| /// [`str::from_utf8_mut`] function. |
| /// |
| /// [`str::from_utf8_mut`]: ./str/fn.from_utf8_mut.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let mut s = String::from("Hello"); |
| /// let bytes = unsafe { s.as_bytes_mut() }; |
| /// |
| /// assert_eq!(b"Hello", bytes); |
| /// ``` |
| /// |
| /// Mutability: |
| /// |
| /// ``` |
| /// let mut s = String::from("🗻∈🌏"); |
| /// |
| /// unsafe { |
| /// let bytes = s.as_bytes_mut(); |
| /// |
| /// bytes[0] = 0xF0; |
| /// bytes[1] = 0x9F; |
| /// bytes[2] = 0x8D; |
| /// bytes[3] = 0x94; |
| /// } |
| /// |
| /// assert_eq!("🍔∈🌏", s); |
| /// ``` |
| #[stable(feature = "str_mut_extras", since = "1.20.0")] |
| #[inline(always)] |
| pub unsafe fn as_bytes_mut(&mut self) -> &mut [u8] { |
| core_str::StrExt::as_bytes_mut(self) |
| } |
| |
| /// Converts a string slice to a raw pointer. |
| /// |
| /// As string slices are a slice of bytes, the raw pointer points to a |
| /// [`u8`]. This pointer will be pointing to the first byte of the string |
| /// slice. |
| /// |
| /// [`u8`]: primitive.u8.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s = "Hello"; |
| /// let ptr = s.as_ptr(); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn as_ptr(&self) -> *const u8 { |
| core_str::StrExt::as_ptr(self) |
| } |
| |
| /// Returns a subslice of `str`. |
| /// |
| /// This is the non-panicking alternative to indexing the `str`. Returns |
| /// [`None`] whenever equivalent indexing operation would panic. |
| /// |
| /// [`None`]: option/enum.Option.html#variant.None |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let v = String::from("🗻∈🌏"); |
| /// |
| /// assert_eq!(Some("🗻"), v.get(0..4)); |
| /// |
| /// // indices not on UTF-8 sequence boundaries |
| /// assert!(v.get(1..).is_none()); |
| /// assert!(v.get(..8).is_none()); |
| /// |
| /// // out of bounds |
| /// assert!(v.get(..42).is_none()); |
| /// ``` |
| #[stable(feature = "str_checked_slicing", since = "1.20.0")] |
| #[inline] |
| pub fn get<I: SliceIndex<str>>(&self, i: I) -> Option<&I::Output> { |
| core_str::StrExt::get(self, i) |
| } |
| |
| /// Returns a mutable subslice of `str`. |
| /// |
| /// This is the non-panicking alternative to indexing the `str`. Returns |
| /// [`None`] whenever equivalent indexing operation would panic. |
| /// |
| /// [`None`]: option/enum.Option.html#variant.None |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut v = String::from("hello"); |
| /// // correct length |
| /// assert!(v.get_mut(0..5).is_some()); |
| /// // out of bounds |
| /// assert!(v.get_mut(..42).is_none()); |
| /// assert_eq!(Some("he"), v.get_mut(0..2).map(|v| &*v)); |
| /// |
| /// assert_eq!("hello", v); |
| /// { |
| /// let s = v.get_mut(0..2); |
| /// let s = s.map(|s| { |
| /// s.make_ascii_uppercase(); |
| /// &*s |
| /// }); |
| /// assert_eq!(Some("HE"), s); |
| /// } |
| /// assert_eq!("HEllo", v); |
| /// ``` |
| #[stable(feature = "str_checked_slicing", since = "1.20.0")] |
| #[inline] |
| pub fn get_mut<I: SliceIndex<str>>(&mut self, i: I) -> Option<&mut I::Output> { |
| core_str::StrExt::get_mut(self, i) |
| } |
| |
| /// Returns a unchecked subslice of `str`. |
| /// |
| /// This is the unchecked alternative to indexing the `str`. |
| /// |
| /// # Safety |
| /// |
| /// Callers of this function are responsible that these preconditions are |
| /// satisfied: |
| /// |
| /// * The starting index must come before the ending index; |
| /// * Indexes must be within bounds of the original slice; |
| /// * Indexes must lie on UTF-8 sequence boundaries. |
| /// |
| /// Failing that, the returned string slice may reference invalid memory or |
| /// violate the invariants communicated by the `str` type. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let v = "🗻∈🌏"; |
| /// unsafe { |
| /// assert_eq!("🗻", v.get_unchecked(0..4)); |
| /// assert_eq!("∈", v.get_unchecked(4..7)); |
| /// assert_eq!("🌏", v.get_unchecked(7..11)); |
| /// } |
| /// ``` |
| #[stable(feature = "str_checked_slicing", since = "1.20.0")] |
| #[inline] |
| pub unsafe fn get_unchecked<I: SliceIndex<str>>(&self, i: I) -> &I::Output { |
| core_str::StrExt::get_unchecked(self, i) |
| } |
| |
| /// Returns a mutable, unchecked subslice of `str`. |
| /// |
| /// This is the unchecked alternative to indexing the `str`. |
| /// |
| /// # Safety |
| /// |
| /// Callers of this function are responsible that these preconditions are |
| /// satisfied: |
| /// |
| /// * The starting index must come before the ending index; |
| /// * Indexes must be within bounds of the original slice; |
| /// * Indexes must lie on UTF-8 sequence boundaries. |
| /// |
| /// Failing that, the returned string slice may reference invalid memory or |
| /// violate the invariants communicated by the `str` type. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let mut v = String::from("🗻∈🌏"); |
| /// unsafe { |
| /// assert_eq!("🗻", v.get_unchecked_mut(0..4)); |
| /// assert_eq!("∈", v.get_unchecked_mut(4..7)); |
| /// assert_eq!("🌏", v.get_unchecked_mut(7..11)); |
| /// } |
| /// ``` |
| #[stable(feature = "str_checked_slicing", since = "1.20.0")] |
| #[inline] |
| pub unsafe fn get_unchecked_mut<I: SliceIndex<str>>(&mut self, i: I) -> &mut I::Output { |
| core_str::StrExt::get_unchecked_mut(self, i) |
| } |
| |
| /// Creates a string slice from another string slice, bypassing safety |
| /// checks. |
| /// |
| /// This is generally not recommended, use with caution! For a safe |
| /// alternative see [`str`] and [`Index`]. |
| /// |
| /// [`str`]: primitive.str.html |
| /// [`Index`]: ops/trait.Index.html |
| /// |
| /// This new slice goes from `begin` to `end`, including `begin` but |
| /// excluding `end`. |
| /// |
| /// To get a mutable string slice instead, see the |
| /// [`slice_mut_unchecked`] method. |
| /// |
| /// [`slice_mut_unchecked`]: #method.slice_mut_unchecked |
| /// |
| /// # Safety |
| /// |
| /// Callers of this function are responsible that three preconditions are |
| /// satisfied: |
| /// |
| /// * `begin` must come before `end`. |
| /// * `begin` and `end` must be byte positions within the string slice. |
| /// * `begin` and `end` must lie on UTF-8 sequence boundaries. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s = "Löwe 老虎 Léopard"; |
| /// |
| /// unsafe { |
| /// assert_eq!("Löwe 老虎 Léopard", s.slice_unchecked(0, 21)); |
| /// } |
| /// |
| /// let s = "Hello, world!"; |
| /// |
| /// unsafe { |
| /// assert_eq!("world", s.slice_unchecked(7, 12)); |
| /// } |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str { |
| core_str::StrExt::slice_unchecked(self, begin, end) |
| } |
| |
| /// Creates a string slice from another string slice, bypassing safety |
| /// checks. |
| /// This is generally not recommended, use with caution! For a safe |
| /// alternative see [`str`] and [`IndexMut`]. |
| /// |
| /// [`str`]: primitive.str.html |
| /// [`IndexMut`]: ops/trait.IndexMut.html |
| /// |
| /// This new slice goes from `begin` to `end`, including `begin` but |
| /// excluding `end`. |
| /// |
| /// To get an immutable string slice instead, see the |
| /// [`slice_unchecked`] method. |
| /// |
| /// [`slice_unchecked`]: #method.slice_unchecked |
| /// |
| /// # Safety |
| /// |
| /// Callers of this function are responsible that three preconditions are |
| /// satisfied: |
| /// |
| /// * `begin` must come before `end`. |
| /// * `begin` and `end` must be byte positions within the string slice. |
| /// * `begin` and `end` must lie on UTF-8 sequence boundaries. |
| #[stable(feature = "str_slice_mut", since = "1.5.0")] |
| #[inline] |
| pub unsafe fn slice_mut_unchecked(&mut self, begin: usize, end: usize) -> &mut str { |
| core_str::StrExt::slice_mut_unchecked(self, begin, end) |
| } |
| |
| /// Divide one string slice into two at an index. |
| /// |
| /// The argument, `mid`, should be a byte offset from the start of the |
| /// string. It must also be on the boundary of a UTF-8 code point. |
| /// |
| /// The two slices returned go from the start of the string slice to `mid`, |
| /// and from `mid` to the end of the string slice. |
| /// |
| /// To get mutable string slices instead, see the [`split_at_mut`] |
| /// method. |
| /// |
| /// [`split_at_mut`]: #method.split_at_mut |
| /// |
| /// # Panics |
| /// |
| /// Panics if `mid` is not on a UTF-8 code point boundary, or if it is |
| /// beyond the last code point of the string slice. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s = "Per Martin-Löf"; |
| /// |
| /// let (first, last) = s.split_at(3); |
| /// |
| /// assert_eq!("Per", first); |
| /// assert_eq!(" Martin-Löf", last); |
| /// ``` |
| #[inline] |
| #[stable(feature = "str_split_at", since = "1.4.0")] |
| pub fn split_at(&self, mid: usize) -> (&str, &str) { |
| core_str::StrExt::split_at(self, mid) |
| } |
| |
| /// Divide one mutable string slice into two at an index. |
| /// |
| /// The argument, `mid`, should be a byte offset from the start of the |
| /// string. It must also be on the boundary of a UTF-8 code point. |
| /// |
| /// The two slices returned go from the start of the string slice to `mid`, |
| /// and from `mid` to the end of the string slice. |
| /// |
| /// To get immutable string slices instead, see the [`split_at`] method. |
| /// |
| /// [`split_at`]: #method.split_at |
| /// |
| /// # Panics |
| /// |
| /// Panics if `mid` is not on a UTF-8 code point boundary, or if it is |
| /// beyond the last code point of the string slice. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let mut s = "Per Martin-Löf".to_string(); |
| /// { |
| /// let (first, last) = s.split_at_mut(3); |
| /// first.make_ascii_uppercase(); |
| /// assert_eq!("PER", first); |
| /// assert_eq!(" Martin-Löf", last); |
| /// } |
| /// assert_eq!("PER Martin-Löf", s); |
| /// ``` |
| #[inline] |
| #[stable(feature = "str_split_at", since = "1.4.0")] |
| pub fn split_at_mut(&mut self, mid: usize) -> (&mut str, &mut str) { |
| core_str::StrExt::split_at_mut(self, mid) |
| } |
| |
| /// Returns an iterator over the [`char`]s of a string slice. |
| /// |
| /// As a string slice consists of valid UTF-8, we can iterate through a |
| /// string slice by [`char`]. This method returns such an iterator. |
| /// |
| /// It's important to remember that [`char`] represents a Unicode Scalar |
| /// Value, and may not match your idea of what a 'character' is. Iteration |
| /// over grapheme clusters may be what you actually want. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let word = "goodbye"; |
| /// |
| /// let count = word.chars().count(); |
| /// assert_eq!(7, count); |
| /// |
| /// let mut chars = word.chars(); |
| /// |
| /// assert_eq!(Some('g'), chars.next()); |
| /// assert_eq!(Some('o'), chars.next()); |
| /// assert_eq!(Some('o'), chars.next()); |
| /// assert_eq!(Some('d'), chars.next()); |
| /// assert_eq!(Some('b'), chars.next()); |
| /// assert_eq!(Some('y'), chars.next()); |
| /// assert_eq!(Some('e'), chars.next()); |
| /// |
| /// assert_eq!(None, chars.next()); |
| /// ``` |
| /// |
| /// Remember, [`char`]s may not match your human intuition about characters: |
| /// |
| /// ``` |
| /// let y = "y̆"; |
| /// |
| /// let mut chars = y.chars(); |
| /// |
| /// assert_eq!(Some('y'), chars.next()); // not 'y̆' |
| /// assert_eq!(Some('\u{0306}'), chars.next()); |
| /// |
| /// assert_eq!(None, chars.next()); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn chars(&self) -> Chars { |
| core_str::StrExt::chars(self) |
| } |
| /// Returns an iterator over the [`char`]s of a string slice, and their |
| /// positions. |
| /// |
| /// As a string slice consists of valid UTF-8, we can iterate through a |
| /// string slice by [`char`]. This method returns an iterator of both |
| /// these [`char`]s, as well as their byte positions. |
| /// |
| /// The iterator yields tuples. The position is first, the [`char`] is |
| /// second. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let word = "goodbye"; |
| /// |
| /// let count = word.char_indices().count(); |
| /// assert_eq!(7, count); |
| /// |
| /// let mut char_indices = word.char_indices(); |
| /// |
| /// assert_eq!(Some((0, 'g')), char_indices.next()); |
| /// assert_eq!(Some((1, 'o')), char_indices.next()); |
| /// assert_eq!(Some((2, 'o')), char_indices.next()); |
| /// assert_eq!(Some((3, 'd')), char_indices.next()); |
| /// assert_eq!(Some((4, 'b')), char_indices.next()); |
| /// assert_eq!(Some((5, 'y')), char_indices.next()); |
| /// assert_eq!(Some((6, 'e')), char_indices.next()); |
| /// |
| /// assert_eq!(None, char_indices.next()); |
| /// ``` |
| /// |
| /// Remember, [`char`]s may not match your human intuition about characters: |
| /// |
| /// ``` |
| /// let yes = "y̆es"; |
| /// |
| /// let mut char_indices = yes.char_indices(); |
| /// |
| /// assert_eq!(Some((0, 'y')), char_indices.next()); // not (0, 'y̆') |
| /// assert_eq!(Some((1, '\u{0306}')), char_indices.next()); |
| /// |
| /// // note the 3 here - the last character took up two bytes |
| /// assert_eq!(Some((3, 'e')), char_indices.next()); |
| /// assert_eq!(Some((4, 's')), char_indices.next()); |
| /// |
| /// assert_eq!(None, char_indices.next()); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn char_indices(&self) -> CharIndices { |
| core_str::StrExt::char_indices(self) |
| } |
| |
| /// An iterator over the bytes of a string slice. |
| /// |
| /// As a string slice consists of a sequence of bytes, we can iterate |
| /// through a string slice by byte. This method returns such an iterator. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let mut bytes = "bors".bytes(); |
| /// |
| /// assert_eq!(Some(b'b'), bytes.next()); |
| /// assert_eq!(Some(b'o'), bytes.next()); |
| /// assert_eq!(Some(b'r'), bytes.next()); |
| /// assert_eq!(Some(b's'), bytes.next()); |
| /// |
| /// assert_eq!(None, bytes.next()); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn bytes(&self) -> Bytes { |
| core_str::StrExt::bytes(self) |
| } |
| |
| /// Split a string slice by whitespace. |
| /// |
| /// The iterator returned will return string slices that are sub-slices of |
| /// the original string slice, separated by any amount of whitespace. |
| /// |
| /// 'Whitespace' is defined according to the terms of the Unicode Derived |
| /// Core Property `White_Space`. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let mut iter = "A few words".split_whitespace(); |
| /// |
| /// assert_eq!(Some("A"), iter.next()); |
| /// assert_eq!(Some("few"), iter.next()); |
| /// assert_eq!(Some("words"), iter.next()); |
| /// |
| /// assert_eq!(None, iter.next()); |
| /// ``` |
| /// |
| /// All kinds of whitespace are considered: |
| /// |
| /// ``` |
| /// let mut iter = " Mary had\ta\u{2009}little \n\t lamb".split_whitespace(); |
| /// assert_eq!(Some("Mary"), iter.next()); |
| /// assert_eq!(Some("had"), iter.next()); |
| /// assert_eq!(Some("a"), iter.next()); |
| /// assert_eq!(Some("little"), iter.next()); |
| /// assert_eq!(Some("lamb"), iter.next()); |
| /// |
| /// assert_eq!(None, iter.next()); |
| /// ``` |
| #[stable(feature = "split_whitespace", since = "1.1.0")] |
| #[inline] |
| pub fn split_whitespace(&self) -> SplitWhitespace { |
| StrExt::split_whitespace(self) |
| } |
| |
| /// An iterator over the lines of a string, as string slices. |
| /// |
| /// Lines are ended with either a newline (`\n`) or a carriage return with |
| /// a line feed (`\r\n`). |
| /// |
| /// The final line ending is optional. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let text = "foo\r\nbar\n\nbaz\n"; |
| /// let mut lines = text.lines(); |
| /// |
| /// assert_eq!(Some("foo"), lines.next()); |
| /// assert_eq!(Some("bar"), lines.next()); |
| /// assert_eq!(Some(""), lines.next()); |
| /// assert_eq!(Some("baz"), lines.next()); |
| /// |
| /// assert_eq!(None, lines.next()); |
| /// ``` |
| /// |
| /// The final line ending isn't required: |
| /// |
| /// ``` |
| /// let text = "foo\nbar\n\r\nbaz"; |
| /// let mut lines = text.lines(); |
| /// |
| /// assert_eq!(Some("foo"), lines.next()); |
| /// assert_eq!(Some("bar"), lines.next()); |
| /// assert_eq!(Some(""), lines.next()); |
| /// assert_eq!(Some("baz"), lines.next()); |
| /// |
| /// assert_eq!(None, lines.next()); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn lines(&self) -> Lines { |
| core_str::StrExt::lines(self) |
| } |
| |
| /// An iterator over the lines of a string. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[rustc_deprecated(since = "1.4.0", reason = "use lines() instead now")] |
| #[inline] |
| #[allow(deprecated)] |
| pub fn lines_any(&self) -> LinesAny { |
| core_str::StrExt::lines_any(self) |
| } |
| |
| /// Returns an iterator of `u16` over the string encoded as UTF-16. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let text = "Zażółć gęślą jaźń"; |
| /// |
| /// let utf8_len = text.len(); |
| /// let utf16_len = text.encode_utf16().count(); |
| /// |
| /// assert!(utf16_len <= utf8_len); |
| /// ``` |
| #[stable(feature = "encode_utf16", since = "1.8.0")] |
| pub fn encode_utf16(&self) -> EncodeUtf16 { |
| EncodeUtf16 { chars: self[..].chars(), extra: 0 } |
| } |
| |
| /// Returns `true` if the given pattern matches a sub-slice of |
| /// this string slice. |
| /// |
| /// Returns `false` if it does not. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let bananas = "bananas"; |
| /// |
| /// assert!(bananas.contains("nana")); |
| /// assert!(!bananas.contains("apples")); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn contains<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool { |
| core_str::StrExt::contains(self, pat) |
| } |
| |
| /// Returns `true` if the given pattern matches a prefix of this |
| /// string slice. |
| /// |
| /// Returns `false` if it does not. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let bananas = "bananas"; |
| /// |
| /// assert!(bananas.starts_with("bana")); |
| /// assert!(!bananas.starts_with("nana")); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn starts_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool { |
| core_str::StrExt::starts_with(self, pat) |
| } |
| |
| /// Returns `true` if the given pattern matches a suffix of this |
| /// string slice. |
| /// |
| /// Returns `false` if it does not. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let bananas = "bananas"; |
| /// |
| /// assert!(bananas.ends_with("anas")); |
| /// assert!(!bananas.ends_with("nana")); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn ends_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool |
| where P::Searcher: ReverseSearcher<'a> |
| { |
| core_str::StrExt::ends_with(self, pat) |
| } |
| |
| /// Returns the byte index of the first character of this string slice that |
| /// matches the pattern. |
| /// |
| /// Returns [`None`] if the pattern doesn't match. |
| /// |
| /// The pattern can be a `&str`, [`char`], or a closure that determines if |
| /// a character matches. |
| /// |
| /// [`char`]: primitive.char.html |
| /// [`None`]: option/enum.Option.html#variant.None |
| /// |
| /// # Examples |
| /// |
| /// Simple patterns: |
| /// |
| /// ``` |
| /// let s = "Löwe 老虎 Léopard"; |
| /// |
| /// assert_eq!(s.find('L'), Some(0)); |
| /// assert_eq!(s.find('é'), Some(14)); |
| /// assert_eq!(s.find("Léopard"), Some(13)); |
| /// ``` |
| /// |
| /// More complex patterns using point-free style and closures: |
| /// |
| /// ``` |
| /// let s = "Löwe 老虎 Léopard"; |
| /// |
| /// assert_eq!(s.find(char::is_whitespace), Some(5)); |
| /// assert_eq!(s.find(char::is_lowercase), Some(1)); |
| /// assert_eq!(s.find(|c: char| c.is_whitespace() || c.is_lowercase()), Some(1)); |
| /// assert_eq!(s.find(|c: char| (c < 'o') && (c > 'a')), Some(4)); |
| /// ``` |
| /// |
| /// Not finding the pattern: |
| /// |
| /// ``` |
| /// let s = "Löwe 老虎 Léopard"; |
| /// let x: &[_] = &['1', '2']; |
| /// |
| /// assert_eq!(s.find(x), None); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn find<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize> { |
| core_str::StrExt::find(self, pat) |
| } |
| |
| /// Returns the byte index of the last character of this string slice that |
| /// matches the pattern. |
| /// |
| /// Returns [`None`] if the pattern doesn't match. |
| /// |
| /// The pattern can be a `&str`, [`char`], or a closure that determines if |
| /// a character matches. |
| /// |
| /// [`char`]: primitive.char.html |
| /// [`None`]: option/enum.Option.html#variant.None |
| /// |
| /// # Examples |
| /// |
| /// Simple patterns: |
| /// |
| /// ``` |
| /// let s = "Löwe 老虎 Léopard"; |
| /// |
| /// assert_eq!(s.rfind('L'), Some(13)); |
| /// assert_eq!(s.rfind('é'), Some(14)); |
| /// ``` |
| /// |
| /// More complex patterns with closures: |
| /// |
| /// ``` |
| /// let s = "Löwe 老虎 Léopard"; |
| /// |
| /// assert_eq!(s.rfind(char::is_whitespace), Some(12)); |
| /// assert_eq!(s.rfind(char::is_lowercase), Some(20)); |
| /// ``` |
| /// |
| /// Not finding the pattern: |
| /// |
| /// ``` |
| /// let s = "Löwe 老虎 Léopard"; |
| /// let x: &[_] = &['1', '2']; |
| /// |
| /// assert_eq!(s.rfind(x), None); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn rfind<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize> |
| where P::Searcher: ReverseSearcher<'a> |
| { |
| core_str::StrExt::rfind(self, pat) |
| } |
| |
| /// An iterator over substrings of this string slice, separated by |
| /// characters matched by a pattern. |
| /// |
| /// The pattern can be a `&str`, [`char`], or a closure that determines the |
| /// split. |
| /// |
| /// # Iterator behavior |
| /// |
| /// The returned iterator will be a [`DoubleEndedIterator`] if the pattern |
| /// allows a reverse search and forward/reverse search yields the same |
| /// elements. This is true for, eg, [`char`] but not for `&str`. |
| /// |
| /// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html |
| /// |
| /// If the pattern allows a reverse search but its results might differ |
| /// from a forward search, the [`rsplit`] method can be used. |
| /// |
| /// [`char`]: primitive.char.html |
| /// [`rsplit`]: #method.rsplit |
| /// |
| /// # Examples |
| /// |
| /// Simple patterns: |
| /// |
| /// ``` |
| /// let v: Vec<&str> = "Mary had a little lamb".split(' ').collect(); |
| /// assert_eq!(v, ["Mary", "had", "a", "little", "lamb"]); |
| /// |
| /// let v: Vec<&str> = "".split('X').collect(); |
| /// assert_eq!(v, [""]); |
| /// |
| /// let v: Vec<&str> = "lionXXtigerXleopard".split('X').collect(); |
| /// assert_eq!(v, ["lion", "", "tiger", "leopard"]); |
| /// |
| /// let v: Vec<&str> = "lion::tiger::leopard".split("::").collect(); |
| /// assert_eq!(v, ["lion", "tiger", "leopard"]); |
| /// |
| /// let v: Vec<&str> = "abc1def2ghi".split(char::is_numeric).collect(); |
| /// assert_eq!(v, ["abc", "def", "ghi"]); |
| /// |
| /// let v: Vec<&str> = "lionXtigerXleopard".split(char::is_uppercase).collect(); |
| /// assert_eq!(v, ["lion", "tiger", "leopard"]); |
| /// ``` |
| /// |
| /// A more complex pattern, using a closure: |
| /// |
| /// ``` |
| /// let v: Vec<&str> = "abc1defXghi".split(|c| c == '1' || c == 'X').collect(); |
| /// assert_eq!(v, ["abc", "def", "ghi"]); |
| /// ``` |
| /// |
| /// If a string contains multiple contiguous separators, you will end up |
| /// with empty strings in the output: |
| /// |
| /// ``` |
| /// let x = "||||a||b|c".to_string(); |
| /// let d: Vec<_> = x.split('|').collect(); |
| /// |
| /// assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]); |
| /// ``` |
| /// |
| /// Contiguous separators are separated by the empty string. |
| /// |
| /// ``` |
| /// let x = "(///)".to_string(); |
| /// let d: Vec<_> = x.split('/').collect(); |
| /// |
| /// assert_eq!(d, &["(", "", "", ")"]); |
| /// ``` |
| /// |
| /// Separators at the start or end of a string are neighbored |
| /// by empty strings. |
| /// |
| /// ``` |
| /// let d: Vec<_> = "010".split("0").collect(); |
| /// assert_eq!(d, &["", "1", ""]); |
| /// ``` |
| /// |
| /// When the empty string is used as a separator, it separates |
| /// every character in the string, along with the beginning |
| /// and end of the string. |
| /// |
| /// ``` |
| /// let f: Vec<_> = "rust".split("").collect(); |
| /// assert_eq!(f, &["", "r", "u", "s", "t", ""]); |
| /// ``` |
| /// |
| /// Contiguous separators can lead to possibly surprising behavior |
| /// when whitespace is used as the separator. This code is correct: |
| /// |
| /// ``` |
| /// let x = " a b c".to_string(); |
| /// let d: Vec<_> = x.split(' ').collect(); |
| /// |
| /// assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]); |
| /// ``` |
| /// |
| /// It does _not_ give you: |
| /// |
| /// ```,ignore |
| /// assert_eq!(d, &["a", "b", "c"]); |
| /// ``` |
| /// |
| /// Use [`split_whitespace`] for this behavior. |
| /// |
| /// [`split_whitespace`]: #method.split_whitespace |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn split<'a, P: Pattern<'a>>(&'a self, pat: P) -> Split<'a, P> { |
| core_str::StrExt::split(self, pat) |
| } |
| |
| /// An iterator over substrings of the given string slice, separated by |
| /// characters matched by a pattern and yielded in reverse order. |
| /// |
| /// The pattern can be a `&str`, [`char`], or a closure that determines the |
| /// split. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// # Iterator behavior |
| /// |
| /// The returned iterator requires that the pattern supports a reverse |
| /// search, and it will be a [`DoubleEndedIterator`] if a forward/reverse |
| /// search yields the same elements. |
| /// |
| /// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html |
| /// |
| /// For iterating from the front, the [`split`] method can be used. |
| /// |
| /// [`split`]: #method.split |
| /// |
| /// # Examples |
| /// |
| /// Simple patterns: |
| /// |
| /// ``` |
| /// let v: Vec<&str> = "Mary had a little lamb".rsplit(' ').collect(); |
| /// assert_eq!(v, ["lamb", "little", "a", "had", "Mary"]); |
| /// |
| /// let v: Vec<&str> = "".rsplit('X').collect(); |
| /// assert_eq!(v, [""]); |
| /// |
| /// let v: Vec<&str> = "lionXXtigerXleopard".rsplit('X').collect(); |
| /// assert_eq!(v, ["leopard", "tiger", "", "lion"]); |
| /// |
| /// let v: Vec<&str> = "lion::tiger::leopard".rsplit("::").collect(); |
| /// assert_eq!(v, ["leopard", "tiger", "lion"]); |
| /// ``` |
| /// |
| /// A more complex pattern, using a closure: |
| /// |
| /// ``` |
| /// let v: Vec<&str> = "abc1defXghi".rsplit(|c| c == '1' || c == 'X').collect(); |
| /// assert_eq!(v, ["ghi", "def", "abc"]); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn rsplit<'a, P: Pattern<'a>>(&'a self, pat: P) -> RSplit<'a, P> |
| where P::Searcher: ReverseSearcher<'a> |
| { |
| core_str::StrExt::rsplit(self, pat) |
| } |
| |
| /// An iterator over substrings of the given string slice, separated by |
| /// characters matched by a pattern. |
| /// |
| /// The pattern can be a `&str`, [`char`], or a closure that determines the |
| /// split. |
| /// |
| /// Equivalent to [`split`], except that the trailing substring |
| /// is skipped if empty. |
| /// |
| /// [`split`]: #method.split |
| /// |
| /// This method can be used for string data that is _terminated_, |
| /// rather than _separated_ by a pattern. |
| /// |
| /// # Iterator behavior |
| /// |
| /// The returned iterator will be a [`DoubleEndedIterator`] if the pattern |
| /// allows a reverse search and forward/reverse search yields the same |
| /// elements. This is true for, eg, [`char`] but not for `&str`. |
| /// |
| /// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html |
| /// [`char`]: primitive.char.html |
| /// |
| /// If the pattern allows a reverse search but its results might differ |
| /// from a forward search, the [`rsplit_terminator`] method can be used. |
| /// |
| /// [`rsplit_terminator`]: #method.rsplit_terminator |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let v: Vec<&str> = "A.B.".split_terminator('.').collect(); |
| /// assert_eq!(v, ["A", "B"]); |
| /// |
| /// let v: Vec<&str> = "A..B..".split_terminator(".").collect(); |
| /// assert_eq!(v, ["A", "", "B", ""]); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn split_terminator<'a, P: Pattern<'a>>(&'a self, pat: P) -> SplitTerminator<'a, P> { |
| core_str::StrExt::split_terminator(self, pat) |
| } |
| |
| /// An iterator over substrings of `self`, separated by characters |
| /// matched by a pattern and yielded in reverse order. |
| /// |
| /// The pattern can be a simple `&str`, [`char`], or a closure that |
| /// determines the split. |
| /// Additional libraries might provide more complex patterns like |
| /// regular expressions. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// Equivalent to [`split`], except that the trailing substring is |
| /// skipped if empty. |
| /// |
| /// [`split`]: #method.split |
| /// |
| /// This method can be used for string data that is _terminated_, |
| /// rather than _separated_ by a pattern. |
| /// |
| /// # Iterator behavior |
| /// |
| /// The returned iterator requires that the pattern supports a |
| /// reverse search, and it will be double ended if a forward/reverse |
| /// search yields the same elements. |
| /// |
| /// For iterating from the front, the [`split_terminator`] method can be |
| /// used. |
| /// |
| /// [`split_terminator`]: #method.split_terminator |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let v: Vec<&str> = "A.B.".rsplit_terminator('.').collect(); |
| /// assert_eq!(v, ["B", "A"]); |
| /// |
| /// let v: Vec<&str> = "A..B..".rsplit_terminator(".").collect(); |
| /// assert_eq!(v, ["", "B", "", "A"]); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn rsplit_terminator<'a, P: Pattern<'a>>(&'a self, pat: P) -> RSplitTerminator<'a, P> |
| where P::Searcher: ReverseSearcher<'a> |
| { |
| core_str::StrExt::rsplit_terminator(self, pat) |
| } |
| |
| /// An iterator over substrings of the given string slice, separated by a |
| /// pattern, restricted to returning at most `n` items. |
| /// |
| /// If `n` substrings are returned, the last substring (the `n`th substring) |
| /// will contain the remainder of the string. |
| /// |
| /// The pattern can be a `&str`, [`char`], or a closure that determines the |
| /// split. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// # Iterator behavior |
| /// |
| /// The returned iterator will not be double ended, because it is |
| /// not efficient to support. |
| /// |
| /// If the pattern allows a reverse search, the [`rsplitn`] method can be |
| /// used. |
| /// |
| /// [`rsplitn`]: #method.rsplitn |
| /// |
| /// # Examples |
| /// |
| /// Simple patterns: |
| /// |
| /// ``` |
| /// let v: Vec<&str> = "Mary had a little lambda".splitn(3, ' ').collect(); |
| /// assert_eq!(v, ["Mary", "had", "a little lambda"]); |
| /// |
| /// let v: Vec<&str> = "lionXXtigerXleopard".splitn(3, "X").collect(); |
| /// assert_eq!(v, ["lion", "", "tigerXleopard"]); |
| /// |
| /// let v: Vec<&str> = "abcXdef".splitn(1, 'X').collect(); |
| /// assert_eq!(v, ["abcXdef"]); |
| /// |
| /// let v: Vec<&str> = "".splitn(1, 'X').collect(); |
| /// assert_eq!(v, [""]); |
| /// ``` |
| /// |
| /// A more complex pattern, using a closure: |
| /// |
| /// ``` |
| /// let v: Vec<&str> = "abc1defXghi".splitn(2, |c| c == '1' || c == 'X').collect(); |
| /// assert_eq!(v, ["abc", "defXghi"]); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn splitn<'a, P: Pattern<'a>>(&'a self, n: usize, pat: P) -> SplitN<'a, P> { |
| core_str::StrExt::splitn(self, n, pat) |
| } |
| |
| /// An iterator over substrings of this string slice, separated by a |
| /// pattern, starting from the end of the string, restricted to returning |
| /// at most `n` items. |
| /// |
| /// If `n` substrings are returned, the last substring (the `n`th substring) |
| /// will contain the remainder of the string. |
| /// |
| /// The pattern can be a `&str`, [`char`], or a closure that |
| /// determines the split. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// # Iterator behavior |
| /// |
| /// The returned iterator will not be double ended, because it is not |
| /// efficient to support. |
| /// |
| /// For splitting from the front, the [`splitn`] method can be used. |
| /// |
| /// [`splitn`]: #method.splitn |
| /// |
| /// # Examples |
| /// |
| /// Simple patterns: |
| /// |
| /// ``` |
| /// let v: Vec<&str> = "Mary had a little lamb".rsplitn(3, ' ').collect(); |
| /// assert_eq!(v, ["lamb", "little", "Mary had a"]); |
| /// |
| /// let v: Vec<&str> = "lionXXtigerXleopard".rsplitn(3, 'X').collect(); |
| /// assert_eq!(v, ["leopard", "tiger", "lionX"]); |
| /// |
| /// let v: Vec<&str> = "lion::tiger::leopard".rsplitn(2, "::").collect(); |
| /// assert_eq!(v, ["leopard", "lion::tiger"]); |
| /// ``` |
| /// |
| /// A more complex pattern, using a closure: |
| /// |
| /// ``` |
| /// let v: Vec<&str> = "abc1defXghi".rsplitn(2, |c| c == '1' || c == 'X').collect(); |
| /// assert_eq!(v, ["ghi", "abc1def"]); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn rsplitn<'a, P: Pattern<'a>>(&'a self, n: usize, pat: P) -> RSplitN<'a, P> |
| where P::Searcher: ReverseSearcher<'a> |
| { |
| core_str::StrExt::rsplitn(self, n, pat) |
| } |
| |
| /// An iterator over the disjoint matches of a pattern within the given string |
| /// slice. |
| /// |
| /// The pattern can be a `&str`, [`char`], or a closure that |
| /// determines if a character matches. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// # Iterator behavior |
| /// |
| /// The returned iterator will be a [`DoubleEndedIterator`] if the pattern |
| /// allows a reverse search and forward/reverse search yields the same |
| /// elements. This is true for, eg, [`char`] but not for `&str`. |
| /// |
| /// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html |
| /// [`char`]: primitive.char.html |
| /// |
| /// If the pattern allows a reverse search but its results might differ |
| /// from a forward search, the [`rmatches`] method can be used. |
| /// |
| /// [`rmatches`]: #method.rmatches |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let v: Vec<&str> = "abcXXXabcYYYabc".matches("abc").collect(); |
| /// assert_eq!(v, ["abc", "abc", "abc"]); |
| /// |
| /// let v: Vec<&str> = "1abc2abc3".matches(char::is_numeric).collect(); |
| /// assert_eq!(v, ["1", "2", "3"]); |
| /// ``` |
| #[stable(feature = "str_matches", since = "1.2.0")] |
| #[inline] |
| pub fn matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> Matches<'a, P> { |
| core_str::StrExt::matches(self, pat) |
| } |
| |
| /// An iterator over the disjoint matches of a pattern within this string slice, |
| /// yielded in reverse order. |
| /// |
| /// The pattern can be a `&str`, [`char`], or a closure that determines if |
| /// a character matches. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// # Iterator behavior |
| /// |
| /// The returned iterator requires that the pattern supports a reverse |
| /// search, and it will be a [`DoubleEndedIterator`] if a forward/reverse |
| /// search yields the same elements. |
| /// |
| /// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html |
| /// |
| /// For iterating from the front, the [`matches`] method can be used. |
| /// |
| /// [`matches`]: #method.matches |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let v: Vec<&str> = "abcXXXabcYYYabc".rmatches("abc").collect(); |
| /// assert_eq!(v, ["abc", "abc", "abc"]); |
| /// |
| /// let v: Vec<&str> = "1abc2abc3".rmatches(char::is_numeric).collect(); |
| /// assert_eq!(v, ["3", "2", "1"]); |
| /// ``` |
| #[stable(feature = "str_matches", since = "1.2.0")] |
| #[inline] |
| pub fn rmatches<'a, P: Pattern<'a>>(&'a self, pat: P) -> RMatches<'a, P> |
| where P::Searcher: ReverseSearcher<'a> |
| { |
| core_str::StrExt::rmatches(self, pat) |
| } |
| |
| /// An iterator over the disjoint matches of a pattern within this string |
| /// slice as well as the index that the match starts at. |
| /// |
| /// For matches of `pat` within `self` that overlap, only the indices |
| /// corresponding to the first match are returned. |
| /// |
| /// The pattern can be a `&str`, [`char`], or a closure that determines |
| /// if a character matches. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// # Iterator behavior |
| /// |
| /// The returned iterator will be a [`DoubleEndedIterator`] if the pattern |
| /// allows a reverse search and forward/reverse search yields the same |
| /// elements. This is true for, eg, [`char`] but not for `&str`. |
| /// |
| /// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html |
| /// |
| /// If the pattern allows a reverse search but its results might differ |
| /// from a forward search, the [`rmatch_indices`] method can be used. |
| /// |
| /// [`rmatch_indices`]: #method.rmatch_indices |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let v: Vec<_> = "abcXXXabcYYYabc".match_indices("abc").collect(); |
| /// assert_eq!(v, [(0, "abc"), (6, "abc"), (12, "abc")]); |
| /// |
| /// let v: Vec<_> = "1abcabc2".match_indices("abc").collect(); |
| /// assert_eq!(v, [(1, "abc"), (4, "abc")]); |
| /// |
| /// let v: Vec<_> = "ababa".match_indices("aba").collect(); |
| /// assert_eq!(v, [(0, "aba")]); // only the first `aba` |
| /// ``` |
| #[stable(feature = "str_match_indices", since = "1.5.0")] |
| #[inline] |
| pub fn match_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> MatchIndices<'a, P> { |
| core_str::StrExt::match_indices(self, pat) |
| } |
| |
| /// An iterator over the disjoint matches of a pattern within `self`, |
| /// yielded in reverse order along with the index of the match. |
| /// |
| /// For matches of `pat` within `self` that overlap, only the indices |
| /// corresponding to the last match are returned. |
| /// |
| /// The pattern can be a `&str`, [`char`], or a closure that determines if a |
| /// character matches. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// # Iterator behavior |
| /// |
| /// The returned iterator requires that the pattern supports a reverse |
| /// search, and it will be a [`DoubleEndedIterator`] if a forward/reverse |
| /// search yields the same elements. |
| /// |
| /// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html |
| /// |
| /// For iterating from the front, the [`match_indices`] method can be used. |
| /// |
| /// [`match_indices`]: #method.match_indices |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let v: Vec<_> = "abcXXXabcYYYabc".rmatch_indices("abc").collect(); |
| /// assert_eq!(v, [(12, "abc"), (6, "abc"), (0, "abc")]); |
| /// |
| /// let v: Vec<_> = "1abcabc2".rmatch_indices("abc").collect(); |
| /// assert_eq!(v, [(4, "abc"), (1, "abc")]); |
| /// |
| /// let v: Vec<_> = "ababa".rmatch_indices("aba").collect(); |
| /// assert_eq!(v, [(2, "aba")]); // only the last `aba` |
| /// ``` |
| #[stable(feature = "str_match_indices", since = "1.5.0")] |
| #[inline] |
| pub fn rmatch_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> RMatchIndices<'a, P> |
| where P::Searcher: ReverseSearcher<'a> |
| { |
| core_str::StrExt::rmatch_indices(self, pat) |
| } |
| |
| /// Returns a string slice with leading and trailing whitespace removed. |
| /// |
| /// 'Whitespace' is defined according to the terms of the Unicode Derived |
| /// Core Property `White_Space`. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s = " Hello\tworld\t"; |
| /// |
| /// assert_eq!("Hello\tworld", s.trim()); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn trim(&self) -> &str { |
| StrExt::trim(self) |
| } |
| |
| /// Returns a string slice with leading whitespace removed. |
| /// |
| /// 'Whitespace' is defined according to the terms of the Unicode Derived |
| /// Core Property `White_Space`. |
| /// |
| /// # Text directionality |
| /// |
| /// A string is a sequence of bytes. 'Left' in this context means the first |
| /// position of that byte string; for a language like Arabic or Hebrew |
| /// which are 'right to left' rather than 'left to right', this will be |
| /// the _right_ side, not the left. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s = " Hello\tworld\t"; |
| /// |
| /// assert_eq!("Hello\tworld\t", s.trim_left()); |
| /// ``` |
| /// |
| /// Directionality: |
| /// |
| /// ``` |
| /// let s = " English"; |
| /// assert!(Some('E') == s.trim_left().chars().next()); |
| /// |
| /// let s = " עברית"; |
| /// assert!(Some('ע') == s.trim_left().chars().next()); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn trim_left(&self) -> &str { |
| StrExt::trim_left(self) |
| } |
| |
| /// Returns a string slice with trailing whitespace removed. |
| /// |
| /// 'Whitespace' is defined according to the terms of the Unicode Derived |
| /// Core Property `White_Space`. |
| /// |
| /// # Text directionality |
| /// |
| /// A string is a sequence of bytes. 'Right' in this context means the last |
| /// position of that byte string; for a language like Arabic or Hebrew |
| /// which are 'right to left' rather than 'left to right', this will be |
| /// the _left_ side, not the right. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s = " Hello\tworld\t"; |
| /// |
| /// assert_eq!(" Hello\tworld", s.trim_right()); |
| /// ``` |
| /// |
| /// Directionality: |
| /// |
| /// ``` |
| /// let s = "English "; |
| /// assert!(Some('h') == s.trim_right().chars().rev().next()); |
| /// |
| /// let s = "עברית "; |
| /// assert!(Some('ת') == s.trim_right().chars().rev().next()); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn trim_right(&self) -> &str { |
| StrExt::trim_right(self) |
| } |
| |
| /// Returns a string slice with all prefixes and suffixes that match a |
| /// pattern repeatedly removed. |
| /// |
| /// The pattern can be a [`char`] or a closure that determines if a |
| /// character matches. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// # Examples |
| /// |
| /// Simple patterns: |
| /// |
| /// ``` |
| /// assert_eq!("11foo1bar11".trim_matches('1'), "foo1bar"); |
| /// assert_eq!("123foo1bar123".trim_matches(char::is_numeric), "foo1bar"); |
| /// |
| /// let x: &[_] = &['1', '2']; |
| /// assert_eq!("12foo1bar12".trim_matches(x), "foo1bar"); |
| /// ``` |
| /// |
| /// A more complex pattern, using a closure: |
| /// |
| /// ``` |
| /// assert_eq!("1foo1barXX".trim_matches(|c| c == '1' || c == 'X'), "foo1bar"); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn trim_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str |
| where P::Searcher: DoubleEndedSearcher<'a> |
| { |
| core_str::StrExt::trim_matches(self, pat) |
| } |
| |
| /// Returns a string slice with all prefixes that match a pattern |
| /// repeatedly removed. |
| /// |
| /// The pattern can be a `&str`, [`char`], or a closure that determines if |
| /// a character matches. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// # Text directionality |
| /// |
| /// A string is a sequence of bytes. 'Left' in this context means the first |
| /// position of that byte string; for a language like Arabic or Hebrew |
| /// which are 'right to left' rather than 'left to right', this will be |
| /// the _right_ side, not the left. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// assert_eq!("11foo1bar11".trim_left_matches('1'), "foo1bar11"); |
| /// assert_eq!("123foo1bar123".trim_left_matches(char::is_numeric), "foo1bar123"); |
| /// |
| /// let x: &[_] = &['1', '2']; |
| /// assert_eq!("12foo1bar12".trim_left_matches(x), "foo1bar12"); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn trim_left_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str { |
| core_str::StrExt::trim_left_matches(self, pat) |
| } |
| |
| /// Returns a string slice with all suffixes that match a pattern |
| /// repeatedly removed. |
| /// |
| /// The pattern can be a `&str`, [`char`], or a closure that |
| /// determines if a character matches. |
| /// |
| /// [`char`]: primitive.char.html |
| /// |
| /// # Text directionality |
| /// |
| /// A string is a sequence of bytes. 'Right' in this context means the last |
| /// position of that byte string; for a language like Arabic or Hebrew |
| /// which are 'right to left' rather than 'left to right', this will be |
| /// the _left_ side, not the right. |
| /// |
| /// # Examples |
| /// |
| /// Simple patterns: |
| /// |
| /// ``` |
| /// assert_eq!("11foo1bar11".trim_right_matches('1'), "11foo1bar"); |
| /// assert_eq!("123foo1bar123".trim_right_matches(char::is_numeric), "123foo1bar"); |
| /// |
| /// let x: &[_] = &['1', '2']; |
| /// assert_eq!("12foo1bar12".trim_right_matches(x), "12foo1bar"); |
| /// ``` |
| /// |
| /// A more complex pattern, using a closure: |
| /// |
| /// ``` |
| /// assert_eq!("1fooX".trim_right_matches(|c| c == '1' || c == 'X'), "1foo"); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn trim_right_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str |
| where P::Searcher: ReverseSearcher<'a> |
| { |
| core_str::StrExt::trim_right_matches(self, pat) |
| } |
| |
| /// Parses this string slice into another type. |
| /// |
| /// Because `parse` is so general, it can cause problems with type |
| /// inference. As such, `parse` is one of the few times you'll see |
| /// the syntax affectionately known as the 'turbofish': `::<>`. This |
| /// helps the inference algorithm understand specifically which type |
| /// you're trying to parse into. |
| /// |
| /// `parse` can parse any type that implements the [`FromStr`] trait. |
| /// |
| /// [`FromStr`]: str/trait.FromStr.html |
| /// |
| /// # Errors |
| /// |
| /// Will return [`Err`] if it's not possible to parse this string slice into |
| /// the desired type. |
| /// |
| /// [`Err`]: str/trait.FromStr.html#associatedtype.Err |
| /// |
| /// # Examples |
| /// |
| /// Basic usage |
| /// |
| /// ``` |
| /// let four: u32 = "4".parse().unwrap(); |
| /// |
| /// assert_eq!(4, four); |
| /// ``` |
| /// |
| /// Using the 'turbofish' instead of annotating `four`: |
| /// |
| /// ``` |
| /// let four = "4".parse::<u32>(); |
| /// |
| /// assert_eq!(Ok(4), four); |
| /// ``` |
| /// |
| /// Failing to parse: |
| /// |
| /// ``` |
| /// let nope = "j".parse::<u32>(); |
| /// |
| /// assert!(nope.is_err()); |
| /// ``` |
| #[inline] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn parse<F: FromStr>(&self) -> Result<F, F::Err> { |
| core_str::StrExt::parse(self) |
| } |
| |
| /// Converts a `Box<str>` into a `Box<[u8]>` without copying or allocating. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s = "this is a string"; |
| /// let boxed_str = s.to_owned().into_boxed_str(); |
| /// let boxed_bytes = boxed_str.into_boxed_bytes(); |
| /// assert_eq!(*boxed_bytes, *s.as_bytes()); |
| /// ``` |
| #[stable(feature = "str_box_extras", since = "1.20.0")] |
| #[inline] |
| pub fn into_boxed_bytes(self: Box<str>) -> Box<[u8]> { |
| self.into() |
| } |
| |
| /// Replaces all matches of a pattern with another string. |
| /// |
| /// `replace` creates a new [`String`], and copies the data from this string slice into it. |
| /// While doing so, it attempts to find matches of a pattern. If it finds any, it |
| /// replaces them with the replacement string slice. |
| /// |
| /// [`String`]: string/struct.String.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s = "this is old"; |
| /// |
| /// assert_eq!("this is new", s.replace("old", "new")); |
| /// ``` |
| /// |
| /// When the pattern doesn't match: |
| /// |
| /// ``` |
| /// let s = "this is old"; |
| /// assert_eq!(s, s.replace("cookie monster", "little lamb")); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn replace<'a, P: Pattern<'a>>(&'a self, from: P, to: &str) -> String { |
| let mut result = String::new(); |
| let mut last_end = 0; |
| for (start, part) in self.match_indices(from) { |
| result.push_str(unsafe { self.slice_unchecked(last_end, start) }); |
| result.push_str(to); |
| last_end = start + part.len(); |
| } |
| result.push_str(unsafe { self.slice_unchecked(last_end, self.len()) }); |
| result |
| } |
| |
| /// Replaces first N matches of a pattern with another string. |
| /// |
| /// `replacen` creates a new [`String`], and copies the data from this string slice into it. |
| /// While doing so, it attempts to find matches of a pattern. If it finds any, it |
| /// replaces them with the replacement string slice at most `count` times. |
| /// |
| /// [`String`]: string/struct.String.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s = "foo foo 123 foo"; |
| /// assert_eq!("new new 123 foo", s.replacen("foo", "new", 2)); |
| /// assert_eq!("faa fao 123 foo", s.replacen('o', "a", 3)); |
| /// assert_eq!("foo foo new23 foo", s.replacen(char::is_numeric, "new", 1)); |
| /// ``` |
| /// |
| /// When the pattern doesn't match: |
| /// |
| /// ``` |
| /// let s = "this is old"; |
| /// assert_eq!(s, s.replacen("cookie monster", "little lamb", 10)); |
| /// ``` |
| #[stable(feature = "str_replacen", since = "1.16.0")] |
| pub fn replacen<'a, P: Pattern<'a>>(&'a self, pat: P, to: &str, count: usize) -> String { |
| // Hope to reduce the times of re-allocation |
| let mut result = String::with_capacity(32); |
| let mut last_end = 0; |
| for (start, part) in self.match_indices(pat).take(count) { |
| result.push_str(unsafe { self.slice_unchecked(last_end, start) }); |
| result.push_str(to); |
| last_end = start + part.len(); |
| } |
| result.push_str(unsafe { self.slice_unchecked(last_end, self.len()) }); |
| result |
| } |
| |
| /// Returns the lowercase equivalent of this string slice, as a new [`String`]. |
| /// |
| /// 'Lowercase' is defined according to the terms of the Unicode Derived Core Property |
| /// `Lowercase`. |
| /// |
| /// Since some characters can expand into multiple characters when changing |
| /// the case, this function returns a [`String`] instead of modifying the |
| /// parameter in-place. |
| /// |
| /// [`String`]: string/struct.String.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s = "HELLO"; |
| /// |
| /// assert_eq!("hello", s.to_lowercase()); |
| /// ``` |
| /// |
| /// A tricky example, with sigma: |
| /// |
| /// ``` |
| /// let sigma = "Σ"; |
| /// |
| /// assert_eq!("σ", sigma.to_lowercase()); |
| /// |
| /// // but at the end of a word, it's ς, not σ: |
| /// let odysseus = "ὈΔΥΣΣΕΎΣ"; |
| /// |
| /// assert_eq!("ὀδυσσεύς", odysseus.to_lowercase()); |
| /// ``` |
| /// |
| /// Languages without case are not changed: |
| /// |
| /// ``` |
| /// let new_year = "农历新年"; |
| /// |
| /// assert_eq!(new_year, new_year.to_lowercase()); |
| /// ``` |
| #[stable(feature = "unicode_case_mapping", since = "1.2.0")] |
| pub fn to_lowercase(&self) -> String { |
| let mut s = String::with_capacity(self.len()); |
| for (i, c) in self[..].char_indices() { |
| if c == 'Σ' { |
| // Σ maps to σ, except at the end of a word where it maps to ς. |
| // This is the only conditional (contextual) but language-independent mapping |
| // in `SpecialCasing.txt`, |
| // so hard-code it rather than have a generic "condition" mechanism. |
| // See https://github.com/rust-lang/rust/issues/26035 |
| map_uppercase_sigma(self, i, &mut s) |
| } else { |
| s.extend(c.to_lowercase()); |
| } |
| } |
| return s; |
| |
| fn map_uppercase_sigma(from: &str, i: usize, to: &mut String) { |
| // See http://www.unicode.org/versions/Unicode7.0.0/ch03.pdf#G33992 |
| // for the definition of `Final_Sigma`. |
| debug_assert!('Σ'.len_utf8() == 2); |
| let is_word_final = case_ignoreable_then_cased(from[..i].chars().rev()) && |
| !case_ignoreable_then_cased(from[i + 2..].chars()); |
| to.push_str(if is_word_final { "ς" } else { "σ" }); |
| } |
| |
| fn case_ignoreable_then_cased<I: Iterator<Item = char>>(iter: I) -> bool { |
| use core::unicode::derived_property::{Cased, Case_Ignorable}; |
| match iter.skip_while(|&c| Case_Ignorable(c)).next() { |
| Some(c) => Cased(c), |
| None => false, |
| } |
| } |
| } |
| |
| /// Returns the uppercase equivalent of this string slice, as a new [`String`]. |
| /// |
| /// 'Uppercase' is defined according to the terms of the Unicode Derived Core Property |
| /// `Uppercase`. |
| /// |
| /// Since some characters can expand into multiple characters when changing |
| /// the case, this function returns a [`String`] instead of modifying the |
| /// parameter in-place. |
| /// |
| /// [`String`]: string/struct.String.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s = "hello"; |
| /// |
| /// assert_eq!("HELLO", s.to_uppercase()); |
| /// ``` |
| /// |
| /// Scripts without case are not changed: |
| /// |
| /// ``` |
| /// let new_year = "农历新年"; |
| /// |
| /// assert_eq!(new_year, new_year.to_uppercase()); |
| /// ``` |
| #[stable(feature = "unicode_case_mapping", since = "1.2.0")] |
| pub fn to_uppercase(&self) -> String { |
| let mut s = String::with_capacity(self.len()); |
| s.extend(self.chars().flat_map(|c| c.to_uppercase())); |
| return s; |
| } |
| |
| /// Escapes each char in `s` with [`char::escape_debug`]. |
| /// |
| /// [`char::escape_debug`]: primitive.char.html#method.escape_debug |
| #[unstable(feature = "str_escape", |
| reason = "return type may change to be an iterator", |
| issue = "27791")] |
| pub fn escape_debug(&self) -> String { |
| self.chars().flat_map(|c| c.escape_debug()).collect() |
| } |
| |
| /// Escapes each char in `s` with [`char::escape_default`]. |
| /// |
| /// [`char::escape_default`]: primitive.char.html#method.escape_default |
| #[unstable(feature = "str_escape", |
| reason = "return type may change to be an iterator", |
| issue = "27791")] |
| pub fn escape_default(&self) -> String { |
| self.chars().flat_map(|c| c.escape_default()).collect() |
| } |
| |
| /// Escapes each char in `s` with [`char::escape_unicode`]. |
| /// |
| /// [`char::escape_unicode`]: primitive.char.html#method.escape_unicode |
| #[unstable(feature = "str_escape", |
| reason = "return type may change to be an iterator", |
| issue = "27791")] |
| pub fn escape_unicode(&self) -> String { |
| self.chars().flat_map(|c| c.escape_unicode()).collect() |
| } |
| |
| /// Converts a [`Box<str>`] into a [`String`] without copying or allocating. |
| /// |
| /// [`String`]: string/struct.String.html |
| /// [`Box<str>`]: boxed/struct.Box.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let string = String::from("birthday gift"); |
| /// let boxed_str = string.clone().into_boxed_str(); |
| /// |
| /// assert_eq!(boxed_str.into_string(), string); |
| /// ``` |
| #[stable(feature = "box_str", since = "1.4.0")] |
| #[inline] |
| pub fn into_string(self: Box<str>) -> String { |
| let slice = Box::<[u8]>::from(self); |
| unsafe { String::from_utf8_unchecked(slice.into_vec()) } |
| } |
| |
| /// Create a [`String`] by repeating a string `n` times. |
| /// |
| /// [`String`]: string/struct.String.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// assert_eq!("abc".repeat(4), String::from("abcabcabcabc")); |
| /// ``` |
| #[stable(feature = "repeat_str", since = "1.16.0")] |
| pub fn repeat(&self, n: usize) -> String { |
| if n == 0 { |
| return String::new(); |
| } |
| |
| // If `n` is larger than zero, it can be split as |
| // `n = 2^expn + rem (2^expn > rem, expn >= 0, rem >= 0)`. |
| // `2^expn` is the number represented by the leftmost '1' bit of `n`, |
| // and `rem` is the remaining part of `n`. |
| |
| // Using `Vec` to access `set_len()`. |
| let mut buf = Vec::with_capacity(self.len() * n); |
| |
| // `2^expn` repetition is done by doubling `buf` `expn`-times. |
| buf.extend(self.as_bytes()); |
| { |
| let mut m = n >> 1; |
| // If `m > 0`, there are remaining bits up to the leftmost '1'. |
| while m > 0 { |
| // `buf.extend(buf)`: |
| unsafe { |
| ptr::copy_nonoverlapping( |
| buf.as_ptr(), |
| (buf.as_mut_ptr() as *mut u8).add(buf.len()), |
| buf.len(), |
| ); |
| // `buf` has capacity of `self.len() * n`. |
| let buf_len = buf.len(); |
| buf.set_len(buf_len * 2); |
| } |
| |
| m >>= 1; |
| } |
| } |
| |
| // `rem` (`= n - 2^expn`) repetition is done by copying |
| // first `rem` repetitions from `buf` itself. |
| let rem_len = self.len() * n - buf.len(); // `self.len() * rem` |
| if rem_len > 0 { |
| // `buf.extend(buf[0 .. rem_len])`: |
| unsafe { |
| // This is non-overlapping since `2^expn > rem`. |
| ptr::copy_nonoverlapping( |
| buf.as_ptr(), |
| (buf.as_mut_ptr() as *mut u8).add(buf.len()), |
| rem_len, |
| ); |
| // `buf.len() + rem_len` equals to `buf.capacity()` (`= self.len() * n`). |
| let buf_cap = buf.capacity(); |
| buf.set_len(buf_cap); |
| } |
| } |
| |
| unsafe { String::from_utf8_unchecked(buf) } |
| } |
| |
| /// Checks if all characters in this string are within the ASCII range. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let ascii = "hello!\n"; |
| /// let non_ascii = "Grüße, Jürgen ❤"; |
| /// |
| /// assert!(ascii.is_ascii()); |
| /// assert!(!non_ascii.is_ascii()); |
| /// ``` |
| #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")] |
| #[inline] |
| pub fn is_ascii(&self) -> bool { |
| // We can treat each byte as character here: all multibyte characters |
| // start with a byte that is not in the ascii range, so we will stop |
| // there already. |
| self.bytes().all(|b| b.is_ascii()) |
| } |
| |
| /// Returns a copy of this string where each character is mapped to its |
| /// ASCII upper case equivalent. |
| /// |
| /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', |
| /// but non-ASCII letters are unchanged. |
| /// |
| /// To uppercase the value in-place, use [`make_ascii_uppercase`]. |
| /// |
| /// To uppercase ASCII characters in addition to non-ASCII characters, use |
| /// [`to_uppercase`]. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let s = "Grüße, Jürgen ❤"; |
| /// |
| /// assert_eq!("GRüßE, JüRGEN ❤", s.to_ascii_uppercase()); |
| /// ``` |
| /// |
| /// [`make_ascii_uppercase`]: #method.make_ascii_uppercase |
| /// [`to_uppercase`]: #method.to_uppercase |
| #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")] |
| #[inline] |
| pub fn to_ascii_uppercase(&self) -> String { |
| let mut bytes = self.as_bytes().to_vec(); |
| bytes.make_ascii_uppercase(); |
| // make_ascii_uppercase() preserves the UTF-8 invariant. |
| unsafe { String::from_utf8_unchecked(bytes) } |
| } |
| |
| /// Returns a copy of this string where each character is mapped to its |
| /// ASCII lower case equivalent. |
| /// |
| /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', |
| /// but non-ASCII letters are unchanged. |
| /// |
| /// To lowercase the value in-place, use [`make_ascii_lowercase`]. |
| /// |
| /// To lowercase ASCII characters in addition to non-ASCII characters, use |
| /// [`to_lowercase`]. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// let s = "Grüße, Jürgen ❤"; |
| /// |
| /// assert_eq!("grüße, jürgen ❤", s.to_ascii_lowercase()); |
| /// ``` |
| /// |
| /// [`make_ascii_lowercase`]: #method.make_ascii_lowercase |
| /// [`to_lowercase`]: #method.to_lowercase |
| #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")] |
| #[inline] |
| pub fn to_ascii_lowercase(&self) -> String { |
| let mut bytes = self.as_bytes().to_vec(); |
| bytes.make_ascii_lowercase(); |
| // make_ascii_lowercase() preserves the UTF-8 invariant. |
| unsafe { String::from_utf8_unchecked(bytes) } |
| } |
| |
| /// Checks that two strings are an ASCII case-insensitive match. |
| /// |
| /// Same as `to_ascii_lowercase(a) == to_ascii_lowercase(b)`, |
| /// but without allocating and copying temporaries. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// assert!("Ferris".eq_ignore_ascii_case("FERRIS")); |
| /// assert!("Ferrös".eq_ignore_ascii_case("FERRöS")); |
| /// assert!(!"Ferrös".eq_ignore_ascii_case("FERRÖS")); |
| /// ``` |
| #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")] |
| #[inline] |
| pub fn eq_ignore_ascii_case(&self, other: &str) -> bool { |
| self.as_bytes().eq_ignore_ascii_case(other.as_bytes()) |
| } |
| |
| /// Converts this string to its ASCII upper case equivalent in-place. |
| /// |
| /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', |
| /// but non-ASCII letters are unchanged. |
| /// |
| /// To return a new uppercased value without modifying the existing one, use |
| /// [`to_ascii_uppercase`]. |
| /// |
| /// [`to_ascii_uppercase`]: #method.to_ascii_uppercase |
| #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")] |
| pub fn make_ascii_uppercase(&mut self) { |
| let me = unsafe { self.as_bytes_mut() }; |
| me.make_ascii_uppercase() |
| } |
| |
| /// Converts this string to its ASCII lower case equivalent in-place. |
| /// |
| /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', |
| /// but non-ASCII letters are unchanged. |
| /// |
| /// To return a new lowercased value without modifying the existing one, use |
| /// [`to_ascii_lowercase`]. |
| /// |
| /// [`to_ascii_lowercase`]: #method.to_ascii_lowercase |
| #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")] |
| pub fn make_ascii_lowercase(&mut self) { |
| let me = unsafe { self.as_bytes_mut() }; |
| me.make_ascii_lowercase() |
| } |
| } |
| |
| /// Converts a boxed slice of bytes to a boxed string slice without checking |
| /// that the string contains valid UTF-8. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let smile_utf8 = Box::new([226, 152, 186]); |
| /// let smile = unsafe { std::str::from_boxed_utf8_unchecked(smile_utf8) }; |
| /// |
| /// assert_eq!("☺", &*smile); |
| /// ``` |
| #[stable(feature = "str_box_extras", since = "1.20.0")] |
| #[inline] |
| pub unsafe fn from_boxed_utf8_unchecked(v: Box<[u8]>) -> Box<str> { |
| Box::from_raw(Box::into_raw(v) as *mut str) |
| } |