// Copyright 2012-2014 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 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. //! Unicode string slices //! //! *[See also the `str` primitive type](../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::clone::Clone; use core::iter::{Iterator, Extend}; use core::option::Option::{self, Some, None}; use core::result::Result; use core::str as core_str; use core::str::pattern::Pattern; use core::str::pattern::{Searcher, ReverseSearcher, DoubleEndedSearcher}; use core::mem; use rustc_unicode::str::{UnicodeStr, Utf16Encoder}; use vec_deque::VecDeque; use borrow::{Borrow, ToOwned}; use string::String; use rustc_unicode; use vec::Vec; use slice::SliceConcatExt; use boxed::Box; pub use core::str::{FromStr, Utf8Error}; #[allow(deprecated)] pub use core::str::{Lines, LinesAny, CharRange}; pub use core::str::{Split, RSplit}; pub use core::str::{SplitN, RSplitN}; pub use core::str::{SplitTerminator, RSplitTerminator}; pub use core::str::{Matches, RMatches}; pub use core::str::{MatchIndices, RMatchIndices}; pub use core::str::{from_utf8, Chars, CharIndices, Bytes}; pub use core::str::{from_utf8_unchecked, ParseBoolError}; pub use rustc_unicode::str::{SplitWhitespace}; pub use core::str::pattern; impl> SliceConcatExt 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::(); 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) } } /// External iterator for a string's UTF-16 code units. /// /// For use with the `std::iter` module. #[derive(Clone)] #[unstable(feature = "str_utf16", issue = "27714")] pub struct Utf16Units<'a> { encoder: Utf16Encoder> } #[stable(feature = "rust1", since = "1.0.0")] impl<'a> Iterator for Utf16Units<'a> { type Item = u16; #[inline] fn next(&mut self) -> Option { self.encoder.next() } #[inline] fn size_hint(&self) -> (usize, Option) { self.encoder.size_hint() } } // Return the initial codepoint accumulator for the first byte. // The first byte is special, only want bottom 5 bits for width 2, 4 bits // for width 3, and 3 bits for width 4 macro_rules! utf8_first_byte { ($byte:expr, $width:expr) => (($byte & (0x7F >> $width)) as u32) } // return the value of $ch updated with continuation byte $byte macro_rules! utf8_acc_cont_byte { ($ch:expr, $byte:expr) => (($ch << 6) | ($byte & 63) as u32) } #[stable(feature = "rust1", since = "1.0.0")] impl Borrow 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()) } } } /// Any string that can be represented as a slice. #[lang = "str"] #[cfg(not(test))] #[stable(feature = "rust1", since = "1.0.0")] impl str { /// Returns the length of `self` in bytes. /// /// # Examples /// /// ``` /// assert_eq!("foo".len(), 3); /// assert_eq!("ƒoo".len(), 4); // fancy f! /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[inline] pub fn len(&self) -> usize { core_str::StrExt::len(self) } /// Returns true if this slice has a length of zero bytes. /// /// # Examples /// /// ``` /// assert!("".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 /// /// ``` /// #![feature(str_char)] /// /// 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)); /// ``` #[unstable(feature = "str_char", reason = "it is unclear whether this method pulls its weight \ with the existence of the char_indices iterator or \ this method may want to be replaced with checked \ slicing", issue = "27754")] #[inline] pub fn is_char_boundary(&self, index: usize) -> bool { core_str::StrExt::is_char_boundary(self, index) } /// Converts `self` to a byte slice. /// /// # Examples /// /// ``` /// assert_eq!("bors".as_bytes(), b"bors"); /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[inline(always)] pub fn as_bytes(&self) -> &[u8] { core_str::StrExt::as_bytes(self) } /// Returns a raw pointer to the `&str`'s buffer. /// /// The caller must ensure that the string outlives this pointer, and /// that it is not /// reallocated (e.g. by pushing to the string). /// /// # Examples /// /// ``` /// let s = "Hello"; /// let p = s.as_ptr(); /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[inline] pub fn as_ptr(&self) -> *const u8 { core_str::StrExt::as_ptr(self) } /// Takes a bytewise slice from a string. /// /// Returns the substring from [`begin`..`end`). /// /// # Safety /// /// Caller must check both UTF-8 sequence boundaries and the boundaries /// of the entire slice as well. /// /// # Examples /// /// ``` /// let s = "Löwe 老虎 Léopard"; /// /// unsafe { /// assert_eq!(s.slice_unchecked(0, 21), "Löwe 老虎 Léopard"); /// } /// ``` #[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) } /// Takes a bytewise mutable slice from a string. /// /// Same as `slice_unchecked`, but works with `&mut str` instead of `&str`. #[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) } /// Given a byte position, return the next code point and its index. /// /// This can be used to iterate over the Unicode code points of a string. /// /// # Panics /// /// If `i` is greater than or equal to the length of the string. /// If `i` is not the index of the beginning of a valid UTF-8 sequence. /// /// # Examples /// /// This example manually iterates through the code points of a string; /// this should normally be /// done by `.chars()` or `.char_indices()`. /// /// ``` /// #![feature(str_char, core)] /// /// use std::str::CharRange; /// /// let s = "中华Việt Nam"; /// let mut i = 0; /// while i < s.len() { /// let CharRange {ch, next} = s.char_range_at(i); /// println!("{}: {}", i, ch); /// i = next; /// } /// ``` /// /// This outputs: /// /// ```text /// 0: 中 /// 3: 华 /// 6: V /// 7: i /// 8: e /// 9: /// 11: /// 13: t /// 14: /// 15: N /// 16: a /// 17: m /// ``` #[unstable(feature = "str_char", reason = "often replaced by char_indices, this method may \ be removed in favor of just char_at() or eventually \ removed altogether", issue = "27754")] #[inline] pub fn char_range_at(&self, start: usize) -> CharRange { core_str::StrExt::char_range_at(self, start) } /// Given a byte position, return the previous `char` and its position. /// /// This function can be used to iterate over a Unicode code points in reverse. /// /// Note that Unicode has many features, such as combining marks, ligatures, /// and direction marks, that need to be taken into account to correctly reverse a string. /// /// Returns 0 for next index if called on start index 0. /// /// # Panics /// /// If `i` is greater than the length of the string. /// If `i` is not an index following a valid UTF-8 sequence. /// /// # Examples /// /// This example manually iterates through the code points of a string; /// this should normally be /// done by `.chars().rev()` or `.char_indices()`. /// /// ``` /// #![feature(str_char, core)] /// /// use std::str::CharRange; /// /// let s = "中华Việt Nam"; /// let mut i = s.len(); /// while i > 0 { /// let CharRange {ch, next} = s.char_range_at_reverse(i); /// println!("{}: {}", i, ch); /// i = next; /// } /// ``` /// /// This outputs: /// /// ```text /// 18: m /// 17: a /// 16: N /// 15: /// 14: t /// 13: /// 11: /// 9: e /// 8: i /// 7: V /// 6: 华 /// 3: 中 /// ``` #[unstable(feature = "str_char", reason = "often replaced by char_indices, this method may \ be removed in favor of just char_at_reverse() or \ eventually removed altogether", issue = "27754")] #[inline] pub fn char_range_at_reverse(&self, start: usize) -> CharRange { core_str::StrExt::char_range_at_reverse(self, start) } /// Given a byte position, return the `char` at that position. /// /// # Panics /// /// If `i` is greater than or equal to the length of the string. /// If `i` is not the index of the beginning of a valid UTF-8 sequence. /// /// # Examples /// /// ``` /// #![feature(str_char)] /// /// let s = "abπc"; /// assert_eq!(s.char_at(1), 'b'); /// assert_eq!(s.char_at(2), 'π'); /// assert_eq!(s.char_at(4), 'c'); /// ``` #[unstable(feature = "str_char", reason = "frequently replaced by the chars() iterator, this \ method may be removed or possibly renamed in the \ future; it is normally replaced by chars/char_indices \ iterators or by getting the first char from a \ subslice", issue = "27754")] #[inline] pub fn char_at(&self, i: usize) -> char { core_str::StrExt::char_at(self, i) } /// Given a byte position, return the `char` at that position, counting /// from the end. /// /// # Panics /// /// If `i` is greater than the length of the string. /// If `i` is not an index following a valid UTF-8 sequence. /// /// # Examples /// /// ``` /// #![feature(str_char)] /// /// let s = "abπc"; /// assert_eq!(s.char_at_reverse(1), 'a'); /// assert_eq!(s.char_at_reverse(2), 'b'); /// assert_eq!(s.char_at_reverse(3), 'π'); /// ``` #[unstable(feature = "str_char", reason = "see char_at for more details, but reverse semantics \ are also somewhat unclear, especially with which \ cases generate panics", issue = "27754")] #[inline] pub fn char_at_reverse(&self, i: usize) -> char { core_str::StrExt::char_at_reverse(self, i) } /// Retrieves the first code point from a `&str` and returns it. /// /// Note that a single Unicode character (grapheme cluster) /// can be composed of multiple `char`s. /// /// This does not allocate a new string; instead, it returns a slice that /// points one code point beyond the code point that was shifted. /// /// `None` is returned if the slice is empty. /// /// # Examples /// /// ``` /// #![feature(str_char)] /// /// let s = "Łódź"; // \u{141}o\u{301}dz\u{301} /// let (c, s1) = s.slice_shift_char().unwrap(); /// /// assert_eq!(c, 'Ł'); /// assert_eq!(s1, "ódź"); /// /// let (c, s2) = s1.slice_shift_char().unwrap(); /// /// assert_eq!(c, 'o'); /// assert_eq!(s2, "\u{301}dz\u{301}"); /// ``` #[unstable(feature = "str_char", reason = "awaiting conventions about shifting and slices and \ may not be warranted with the existence of the chars \ and/or char_indices iterators", issue = "27754")] #[inline] pub fn slice_shift_char(&self) -> Option<(char, &str)> { core_str::StrExt::slice_shift_char(self) } /// Divide one string slice into two at an index. /// /// The index `mid` is a byte offset from the start of the string /// that must be on a `char` boundary. /// /// Return slices `&self[..mid]` and `&self[mid..]`. /// /// # Panics /// /// Panics if `mid` is beyond the last code point of the string, /// or if it is not on a `char` boundary. /// /// # Examples /// ``` /// let s = "Löwe 老虎 Léopard"; /// let first_space = s.find(' ').unwrap_or(s.len()); /// let (a, b) = s.split_at(first_space); /// /// assert_eq!(a, "Löwe"); /// assert_eq!(b, " 老虎 Léopard"); /// ``` #[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. #[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) } /// An iterator over the code points of `self`. /// /// In Unicode relationship between code points and characters is complex. /// A single character may be composed of multiple code points /// (e.g. diacritical marks added to a letter), and a single code point /// (e.g. Hangul syllable) may contain multiple characters. /// /// For iteration over human-readable characters a grapheme cluster iterator /// may be more appropriate. See the [unicode-segmentation crate][1]. /// /// [1]: https://crates.io/crates/unicode-segmentation /// /// # Examples /// /// ``` /// let v: Vec = "ASCII żółć 🇨🇭 한".chars().collect(); /// /// assert_eq!(v, ['A', 'S', 'C', 'I', 'I', ' ', /// 'z', '\u{307}', 'o', '\u{301}', 'ł', 'c', '\u{301}', ' ', /// '\u{1f1e8}', '\u{1f1ed}', ' ', '한']); /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[inline] pub fn chars(&self) -> Chars { core_str::StrExt::chars(self) } /// An iterator over the `char`s of `self` and their byte offsets. /// /// # Examples /// /// ``` /// let v: Vec<(usize, char)> = "A🇨🇭".char_indices().collect(); /// let b = vec![(0, 'A'), (1, '\u{1f1e8}'), (5, '\u{1f1ed}')]; /// /// assert_eq!(v, b); /// ``` #[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 `self`. /// /// # Examples /// /// ``` /// let v: Vec = "bors".bytes().collect(); /// /// assert_eq!(v, b"bors".to_vec()); /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[inline] pub fn bytes(&self) -> Bytes { core_str::StrExt::bytes(self) } /// An iterator over the non-empty substrings of `self` which contain no whitespace, /// and which are separated by any amount of whitespace. /// /// # Examples /// /// ``` /// let some_words = " Mary had\ta\u{2009}little \n\t lamb"; /// let v: Vec<&str> = some_words.split_whitespace().collect(); /// /// assert_eq!(v, ["Mary", "had", "a", "little", "lamb"]); /// ``` #[stable(feature = "split_whitespace", since = "1.1.0")] #[inline] pub fn split_whitespace(&self) -> SplitWhitespace { UnicodeStr::split_whitespace(self) } /// An iterator over the lines of a string, separated by `\n` or `\r\n`. /// /// This does not include the empty string after a trailing newline or CRLF. /// /// # Examples /// /// ``` /// let four_lines = "foo\nbar\n\r\nbaz"; /// let v: Vec<&str> = four_lines.lines().collect(); /// /// assert_eq!(v, ["foo", "bar", "", "baz"]); /// ``` /// /// Leaving off the trailing character: /// /// ``` /// let four_lines = "foo\r\nbar\n\nbaz\n"; /// let v: Vec<&str> = four_lines.lines().collect(); /// /// assert_eq!(v, ["foo", "bar", "", "baz"]); /// ``` #[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, separated by either /// `\n` or `\r\n`. /// /// As with `.lines()`, this does not include an empty trailing line. /// /// # Examples /// /// ``` /// let four_lines = "foo\r\nbar\n\r\nbaz"; /// let v: Vec<&str> = four_lines.lines_any().collect(); /// /// assert_eq!(v, ["foo", "bar", "", "baz"]); /// ``` /// /// Leaving off the trailing character: /// /// ``` /// let four_lines = "foo\r\nbar\n\r\nbaz\n"; /// let v: Vec<&str> = four_lines.lines_any().collect(); /// /// assert_eq!(v, ["foo", "bar", "", "baz"]); /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[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. #[unstable(feature = "str_utf16", reason = "this functionality may only be provided by libunicode", issue = "27714")] pub fn utf16_units(&self) -> Utf16Units { Utf16Units { encoder: Utf16Encoder::new(self[..].chars()) } } /// Returns `true` if `self` contains another `&str`. /// /// # Examples /// /// ``` /// assert!("bananas".contains("nana")); /// /// assert!(!"bananas".contains("foobar")); /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn contains<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool { core_str::StrExt::contains(self, pat) } /// Returns `true` if the given `&str` is a prefix of the string. /// /// # Examples /// /// ``` /// assert!("banana".starts_with("ba")); /// ``` #[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 `&str` is a suffix of the string. /// /// # Examples /// /// ```rust /// assert!("banana".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 `self` that matches /// the pattern, if it /// exists. /// /// Returns `None` if it doesn't exist. /// /// The pattern can be a simple `&str`, `char`, or a closure that /// determines if a character matches. /// /// # 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 with 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)); /// ``` /// /// 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")] pub fn find<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option { core_str::StrExt::find(self, pat) } /// Returns the byte index of the last character of `self` that /// matches the pattern, if it /// exists. /// /// Returns `None` if it doesn't exist. /// /// The pattern can be a simple `&str`, `char`, /// or a closure that determines if a character matches. /// /// # 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")] pub fn rfind<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option where P::Searcher: ReverseSearcher<'a> { core_str::StrExt::rfind(self, pat) } /// An iterator over substrings of `self`, separated by characters /// matched by a pattern. /// /// 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. /// /// # Iterator behavior /// /// The returned iterator will be double ended 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`. /// /// If the pattern allows a reverse search but its results might differ /// from a forward search, `rsplit()` can be used. /// /// # 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"]); /// ``` /// /// This 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: /// /// ```rust,ignore /// assert_eq!(d, &["a", "b", "c"]); /// ``` /// /// Use [`.split_whitespace()`][split_whitespace] for this behavior. /// /// [split_whitespace]: #method.split_whitespace #[stable(feature = "rust1", since = "1.0.0")] 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 `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. /// /// # 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, `split()` can be used. /// /// # Examples /// /// Simple patterns: /// /// ```rust /// 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")] 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 `self`, separated by characters /// matched by a pattern. /// /// 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. /// /// Equivalent to `split`, except that the trailing substring /// is skipped if empty. /// /// This method can be used for string data that is _terminated_, /// rather than _separated_ by a pattern. /// /// # Iterator behavior /// /// The returned iterator will be double ended 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`. /// /// If the pattern allows a reverse search but its results might differ /// from a forward search, `rsplit_terminator()` can be used. /// /// # Examples /// /// ``` /// 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")] 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. /// /// Equivalent to `split`, except that the trailing substring is /// skipped if empty. /// /// 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, `split_terminator()` can be used. /// /// # 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")] 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 `self`, separated by a pattern, /// restricted to returning /// at most `count` items. /// /// The last element returned, if any, will contain the remainder of the /// string. /// 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. /// /// # Iterator behavior /// /// The returned iterator will not be double ended, because it is /// not efficient to support. /// /// If the pattern allows a reverse search, `rsplitn()` can be used. /// /// # 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")] pub fn splitn<'a, P: Pattern<'a>>(&'a self, count: usize, pat: P) -> SplitN<'a, P> { core_str::StrExt::splitn(self, count, pat) } /// An iterator over substrings of `self`, separated by a pattern, /// starting from the end of the string, restricted to returning /// at most `count` items. /// /// The last element returned, if any, will contain the remainder of the /// string. /// /// 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. /// /// # Iterator behavior /// /// The returned iterator will not be double ended, because it is not /// efficient to support. /// /// `splitn()` can be used for splitting from the front. /// /// # 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")] pub fn rsplitn<'a, P: Pattern<'a>>(&'a self, count: usize, pat: P) -> RSplitN<'a, P> where P::Searcher: ReverseSearcher<'a> { core_str::StrExt::rsplitn(self, count, pat) } /// An iterator over the matches of a pattern within `self`. /// /// The pattern can be a simple `&str`, `char`, or a closure that /// determines if a character matches. /// Additional libraries might provide more complex patterns like /// regular expressions. /// /// # Iterator behavior /// /// The returned iterator will be double ended 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`. /// /// If the pattern allows a reverse search but its results might differ /// from a forward search, `rmatches()` can be used. /// /// # Examples /// /// ``` /// 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")] pub fn matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> Matches<'a, P> { core_str::StrExt::matches(self, pat) } /// An iterator over the matches of a pattern within `self`, yielded in /// reverse order. /// /// The pattern can be a simple `&str`, `char`, or a closure that /// determines if a character matches. /// Additional libraries might provide more complex patterns like /// regular expressions. /// /// # 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, `matches()` can be used. /// /// # Examples /// /// ``` /// 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")] 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 `self` 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 simple `&str`, `char`, or a closure that determines /// if a character matches. Additional libraries might provide more complex /// patterns like regular expressions. /// /// # Iterator behavior /// /// The returned iterator will be double ended 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`. /// /// If the pattern allows a reverse search but its results might differ /// from a forward search, `rmatch_indices()` can be used. /// /// # Examples /// /// ``` /// #![feature(str_match_indices)] /// /// 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")] 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 simple `&str`, `char`, or a closure that determines /// if a character matches. Additional libraries might provide more complex /// patterns like regular expressions. /// /// # 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, `match_indices()` can be used. /// /// # Examples /// /// ``` /// #![feature(str_match_indices)] /// /// 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")] 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 `&str` with leading and trailing whitespace removed. /// /// # Examples /// /// ``` /// let s = " Hello\tworld\t"; /// assert_eq!(s.trim(), "Hello\tworld"); /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn trim(&self) -> &str { UnicodeStr::trim(self) } /// Returns a `&str` with leading whitespace removed. /// /// # Examples /// /// ``` /// let s = " Hello\tworld\t"; /// assert_eq!(s.trim_left(), "Hello\tworld\t"); /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn trim_left(&self) -> &str { UnicodeStr::trim_left(self) } /// Returns a `&str` with trailing whitespace removed. /// /// # Examples /// /// ``` /// let s = " Hello\tworld\t"; /// assert_eq!(s.trim_right(), " Hello\tworld"); /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn trim_right(&self) -> &str { UnicodeStr::trim_right(self) } /// Returns a string with all pre- and suffixes that match a pattern /// repeatedly removed. /// /// The pattern can be a simple `char`, or a closure that determines /// if a character matches. /// /// # 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 with all prefixes that match a pattern /// repeatedly removed. /// /// The pattern can be a simple `&str`, `char`, or a closure that /// determines if a character matches. /// /// # Examples /// /// ``` /// 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 with all suffixes that match a pattern /// repeatedly removed. /// /// The pattern can be a simple `&str`, `char`, or a closure that /// determines if a character matches. /// /// # 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_left_matches(|c| c == '1' || c == 'X'), "fooX"); /// ``` #[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 `self` into the specified type. /// /// # Failure /// /// Will return `Err` if it's not possible to parse `self` into the type. /// /// # Example /// /// ``` /// assert_eq!("4".parse::(), Ok(4)); /// ``` /// /// Failing: /// /// ``` /// assert!("j".parse::().is_err()); /// ``` #[inline] #[stable(feature = "rust1", since = "1.0.0")] pub fn parse(&self) -> Result { core_str::StrExt::parse(self) } /// Replaces all occurrences of one string with another. /// /// `replace` takes two arguments, a sub-`&str` to find in `self`, and a /// second `&str` to /// replace it with. If the original `&str` isn't found, no change occurs. /// /// # Examples /// /// ``` /// let s = "this is old"; /// /// assert_eq!(s.replace("old", "new"), "this is new"); /// ``` /// /// When a `&str` isn't found: /// /// ``` /// let s = "this is old"; /// assert_eq!(s.replace("cookie monster", "little lamb"), s); /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn replace(&self, from: &str, 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 } /// Returns the lowercase equivalent of this string. /// /// # Examples /// /// ``` /// let s = "HELLO"; /// assert_eq!(s.to_lowercase(), "hello"); /// ``` #[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" mechanim. // 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>(iter: I) -> bool { use rustc_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. /// /// # Examples /// /// ``` /// let s = "hello"; /// assert_eq!(s.to_uppercase(), "HELLO"); /// ``` #[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_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`. #[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 the `Box` into a `String` without copying or allocating. #[stable(feature = "box_str", since = "1.4.0")] pub fn into_string(self: Box) -> String { unsafe { let slice = mem::transmute::, Box<[u8]>>(self); String::from_utf8_unchecked(slice.into_vec()) } } }