Struct slint::SharedString

pub struct SharedString { /* private fields */ }
Expand description

A string type used by the Slint run-time.

SharedString uses implicit data sharing to make it efficient to pass around copies. When cloning, a reference to the data is cloned, not the data itself. The data itself is only copied when modifying it, for example using push_str. This is also called copy-on-write.

Under the hood the string data is UTF-8 encoded and it is always terminated with a null character.

SharedString implements [Deref<Target=str>] so it can be easily passed to any function taking a &str. It also implement From such that it an easily be converted to and from the typical rust String type with .into()

Implementationsยง

ยง

impl SharedString

pub fn new() -> SharedString

Creates a new empty string

Same as SharedString::default()

pub fn len(&self) -> usize

Size of the string, in bytes. This excludes the terminating null character.

pub fn is_empty(&self) -> bool

Return true if the String is empty

pub fn as_str(&self) -> &str

Return a slice to the string

pub fn push_str(&mut self, x: &str)

Append a string to this string

let mut hello = SharedString::from("Hello");
hello.push_str(", ");
hello.push_str("World");
hello.push_str("!");
assert_eq!(hello, "Hello, World!");

Methods from Deref<Target = str>ยง

1.0.0 ยท source

pub fn len(&self) -> usize

Returns the length of self.

This length is in bytes, not chars or graphemes. In other words, it might not be what a human considers the length of the string.

Examples

Basic usage:

let len = "foo".len();
assert_eq!(3, len);

assert_eq!("ฦ’oo".len(), 4); // fancy f!
assert_eq!("ฦ’oo".chars().count(), 3);
1.0.0 ยท source

pub fn is_empty(&self) -> bool

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());
1.9.0 ยท source

pub fn is_char_boundary(&self, index: usize) -> bool

Checks that index-th byte is the first byte in a UTF-8 code point sequence or the end of the string.

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 = "Lรถwe ่€่™Ž Lรฉopard";
assert!(s.is_char_boundary(0));
// start of `่€`
assert!(s.is_char_boundary(6));
assert!(s.is_char_boundary(s.len()));

// second byte of `รถ`
assert!(!s.is_char_boundary(2));

// third byte of `่€`
assert!(!s.is_char_boundary(8));
source

pub fn floor_char_boundary(&self, index: usize) -> usize

๐Ÿ”ฌThis is a nightly-only experimental API. (round_char_boundary)

Finds the closest x not exceeding index where is_char_boundary(x) is true.

This method can help you truncate a string so that itโ€™s still valid UTF-8, but doesnโ€™t exceed a given number of bytes. Note that this is done purely at the character level and can still visually split graphemes, even though the underlying characters arenโ€™t split. For example, the emoji ๐Ÿง‘โ€๐Ÿ”ฌ (scientist) could be split so that the string only includes ๐Ÿง‘ (person) instead.

Examples
#![feature(round_char_boundary)]
let s = "โค๏ธ๐Ÿงก๐Ÿ’›๐Ÿ’š๐Ÿ’™๐Ÿ’œ";
assert_eq!(s.len(), 26);
assert!(!s.is_char_boundary(13));

let closest = s.floor_char_boundary(13);
assert_eq!(closest, 10);
assert_eq!(&s[..closest], "โค๏ธ๐Ÿงก");
source

pub fn ceil_char_boundary(&self, index: usize) -> usize

๐Ÿ”ฌThis is a nightly-only experimental API. (round_char_boundary)

Finds the closest x not below index where is_char_boundary(x) is true.

This method is the natural complement to floor_char_boundary. See that method for more details.

Panics

Panics if index > self.len().

Examples
#![feature(round_char_boundary)]
let s = "โค๏ธ๐Ÿงก๐Ÿ’›๐Ÿ’š๐Ÿ’™๐Ÿ’œ";
assert_eq!(s.len(), 26);
assert!(!s.is_char_boundary(13));

let closest = s.ceil_char_boundary(13);
assert_eq!(closest, 14);
assert_eq!(&s[..closest], "โค๏ธ๐Ÿงก๐Ÿ’›");
1.0.0 ยท source

pub fn as_bytes(&self) -> &[u8] โ“˜

Converts a string slice to a byte slice. To convert the byte slice back into a string slice, use the from_utf8 function.

Examples

Basic usage:

let bytes = "bors".as_bytes();
assert_eq!(b"bors", bytes);
1.0.0 ยท source

pub fn as_ptr(&self) -> *const u8

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.

The caller must ensure that the returned pointer is never written to. If you need to mutate the contents of the string slice, use as_mut_ptr.

Examples

Basic usage:

let s = "Hello";
let ptr = s.as_ptr();
1.20.0 ยท source

pub fn get<I>(&self, i: I) -> Option<&<I as SliceIndex<str>>::Output>where I: SliceIndex<str>,

Returns a subslice of str.

This is the non-panicking alternative to indexing the str. Returns None whenever equivalent indexing operation would panic.

Examples
let v = String::from("๐Ÿ—ปโˆˆ๐ŸŒ");

assert_eq!(Some("๐Ÿ—ป"), 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());
1.20.0 ยท source

pub unsafe fn get_unchecked<I>(&self, i: I) -> &<I as SliceIndex<str>>::Outputwhere I: SliceIndex<str>,

Returns an 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 not exceed 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 = "๐Ÿ—ปโˆˆ๐ŸŒ";
unsafe {
    assert_eq!("๐Ÿ—ป", v.get_unchecked(0..4));
    assert_eq!("โˆˆ", v.get_unchecked(4..7));
    assert_eq!("๐ŸŒ", v.get_unchecked(7..11));
}
1.0.0 ยท source

pub unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str

๐Ÿ‘ŽDeprecated since 1.29.0: use get_unchecked(begin..end) instead

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.

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.

Safety

Callers of this function are responsible that three preconditions are satisfied:

  • begin must not exceed 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 = "Lรถwe ่€่™Ž Lรฉopard";

unsafe {
    assert_eq!("Lรถwe ่€่™Ž Lรฉopard", s.slice_unchecked(0, 21));
}

let s = "Hello, world!";

unsafe {
    assert_eq!("world", s.slice_unchecked(7, 12));
}
1.4.0 ยท source

pub fn split_at(&self, mid: usize) -> (&str, &str)

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.

Panics

Panics if mid is not on a UTF-8 code point boundary, or if it is past the end of the last code point of the string slice.

Examples

Basic usage:

let s = "Per Martin-Lรถf";

let (first, last) = s.split_at(3);

assert_eq!("Per", first);
assert_eq!(" Martin-Lรถf", last);
1.0.0 ยท source

pub fn chars(&self) -> Chars<'_>

Returns an iterator over the chars 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.

Itโ€™s important to remember that char represents a Unicode Scalar Value, and might not match your idea of what a โ€˜characterโ€™ is. Iteration over grapheme clusters may be what you actually want. This functionality is not provided by Rustโ€™s standard library, check crates.io instead.

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, chars might not match your intuition about characters:

let y = "yฬ†";

let mut chars = y.chars();

assert_eq!(Some('y'), chars.next()); // not 'yฬ†'
assert_eq!(Some('\u{0306}'), chars.next());

assert_eq!(None, chars.next());
1.0.0 ยท source

pub fn char_indices(&self) -> CharIndices<'_>

Returns an iterator over the chars 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 chars, as well as their byte positions.

The iterator yields tuples. The position is first, the char is second.

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, chars might not match your intuition about characters:

let yes = "yฬ†es";

let mut char_indices = yes.char_indices();

assert_eq!(Some((0, 'y')), char_indices.next()); // not (0, 'yฬ†')
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());
1.0.0 ยท source

pub fn bytes(&self) -> Bytes<'_>

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());
1.1.0 ยท source

pub fn split_whitespace(&self) -> SplitWhitespace<'_>

Splits 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.

โ€˜Whitespaceโ€™ is defined according to the terms of the Unicode Derived Core Property White_Space. If you only want to split on ASCII whitespace instead, use split_ascii_whitespace.

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());

If the string is empty or all whitespace, the iterator yields no string slices:

assert_eq!("".split_whitespace().next(), None);
assert_eq!("   ".split_whitespace().next(), None);
1.34.0 ยท source

pub fn split_ascii_whitespace(&self) -> SplitAsciiWhitespace<'_>

Splits a string slice by ASCII whitespace.

The iterator returned will return string slices that are sub-slices of the original string slice, separated by any amount of ASCII whitespace.

To split by Unicode Whitespace instead, use split_whitespace.

Examples

Basic usage:

let mut iter = "A few words".split_ascii_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 ASCII whitespace are considered:

let mut iter = " Mary   had\ta little  \n\t lamb".split_ascii_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());

If the string is empty or all ASCII whitespace, the iterator yields no string slices:

assert_eq!("".split_ascii_whitespace().next(), None);
assert_eq!("   ".split_ascii_whitespace().next(), None);
1.0.0 ยท source

pub fn lines(&self) -> Lines<'_>

An iterator over the lines of a string, as string slices.

Lines are split at line endings that are either newlines (\n) or sequences of a carriage return followed by a line feed (\r\n).

Line terminators are not included in the lines returned by the iterator.

The final line ending is optional. A string that ends with a final line ending will return the same lines as an otherwise identical string without a final line ending.

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 isnโ€™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());
1.0.0 ยท source

pub fn lines_any(&self) -> LinesAny<'_>

๐Ÿ‘ŽDeprecated since 1.4.0: use lines() instead now

An iterator over the lines of a string.

1.8.0 ยท source

pub fn encode_utf16(&self) -> EncodeUtf16<'_>

Returns an iterator of u16 over the string encoded as UTF-16.

Examples

Basic usage:

let text = "Zaลผรณล‚ฤ‡ gฤ™ล›lฤ… jaลบล„";

let utf8_len = text.len();
let utf16_len = text.encode_utf16().count();

assert!(utf16_len <= utf8_len);
1.0.0 ยท source

pub fn contains<'a, P>(&'a self, pat: P) -> boolwhere P: Pattern<'a>,

Returns true if the given pattern matches a sub-slice of this string slice.

Returns false if it does not.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

Basic usage:

let bananas = "bananas";

assert!(bananas.contains("nana"));
assert!(!bananas.contains("apples"));
1.0.0 ยท source

pub fn starts_with<'a, P>(&'a self, pat: P) -> boolwhere P: Pattern<'a>,

Returns true if the given pattern matches a prefix of this string slice.

Returns false if it does not.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

Basic usage:

let bananas = "bananas";

assert!(bananas.starts_with("bana"));
assert!(!bananas.starts_with("nana"));
1.0.0 ยท source

pub fn ends_with<'a, P>(&'a self, pat: P) -> boolwhere P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

Returns true if the given pattern matches a suffix of this string slice.

Returns false if it does not.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

Basic usage:

let bananas = "bananas";

assert!(bananas.ends_with("anas"));
assert!(!bananas.ends_with("nana"));
1.0.0 ยท source

pub fn find<'a, P>(&'a self, pat: P) -> Option<usize>where P: Pattern<'a>,

Returns the byte index of the first character of this string slice that matches the pattern.

Returns None if the pattern doesnโ€™t match.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

Simple patterns:

let s = "Lรถwe ่€่™Ž Lรฉopard Gepardi";

assert_eq!(s.find('L'), Some(0));
assert_eq!(s.find('รฉ'), Some(14));
assert_eq!(s.find("pard"), Some(17));

More complex patterns using point-free style and closures:

let s = "Lรถwe ่€่™Ž Lรฉopard";

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 = "Lรถwe ่€่™Ž Lรฉopard";
let x: &[_] = &['1', '2'];

assert_eq!(s.find(x), None);
1.0.0 ยท source

pub fn rfind<'a, P>(&'a self, pat: P) -> Option<usize>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

Returns the byte index for the first character of the last match of the pattern in this string slice.

Returns None if the pattern doesnโ€™t match.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples

Simple patterns:

let s = "Lรถwe ่€่™Ž Lรฉopard Gepardi";

assert_eq!(s.rfind('L'), Some(13));
assert_eq!(s.rfind('รฉ'), Some(14));
assert_eq!(s.rfind("pard"), Some(24));

More complex patterns with closures:

let s = "Lรถwe ่€่™Ž Lรฉopard";

assert_eq!(s.rfind(char::is_whitespace), Some(12));
assert_eq!(s.rfind(char::is_lowercase), Some(20));

Not finding the pattern:

let s = "Lรถwe ่€่™Ž Lรฉopard";
let x: &[_] = &['1', '2'];

assert_eq!(s.rfind(x), None);
1.0.0 ยท source

pub fn split<'a, P>(&'a self, pat: P) -> Split<'a, P>where P: Pattern<'a>,

An iterator over substrings of this string slice, separated by characters matched by a pattern.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

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, e.g., char, but not for &str.

If the pattern allows a reverse search but its results might differ from a forward search, the rsplit method 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"]);

If the pattern is a slice of chars, split on each occurrence of any of the characters:

let v: Vec<&str> = "2020-11-03 23:59".split(&['-', ' ', ':', '@'][..]).collect();
assert_eq!(v, ["2020", "11", "03", "23", "59"]);

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:

โ“˜
assert_eq!(d, &["a", "b", "c"]);

Use split_whitespace for this behavior.

1.51.0 ยท source

pub fn split_inclusive<'a, P>(&'a self, pat: P) -> SplitInclusive<'a, P>where P: Pattern<'a>,

An iterator over substrings of this string slice, separated by characters matched by a pattern. Differs from the iterator produced by split in that split_inclusive leaves the matched part as the terminator of the substring.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples
let v: Vec<&str> = "Mary had a little lamb\nlittle lamb\nlittle lamb."
    .split_inclusive('\n').collect();
assert_eq!(v, ["Mary had a little lamb\n", "little lamb\n", "little lamb."]);

If the last element of the string is matched, that element will be considered the terminator of the preceding substring. That substring will be the last item returned by the iterator.

let v: Vec<&str> = "Mary had a little lamb\nlittle lamb\nlittle lamb.\n"
    .split_inclusive('\n').collect();
assert_eq!(v, ["Mary had a little lamb\n", "little lamb\n", "little lamb.\n"]);
1.0.0 ยท source

pub fn rsplit<'a, P>(&'a self, pat: P) -> RSplit<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

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, a slice of chars, or a function or closure that determines if a character matches.

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.

For iterating from the front, the split method can be used.

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"]);
1.0.0 ยท source

pub fn split_terminator<'a, P>(&'a self, pat: P) -> SplitTerminator<'a, P>where P: Pattern<'a>,

An iterator over substrings of the given string slice, separated by characters matched by a pattern.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

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 a DoubleEndedIterator if the pattern allows a reverse search and forward/reverse search yields the same elements. This is true for, e.g., char, but not for &str.

If the pattern allows a reverse search but its results might differ from a forward search, the rsplit_terminator method can be used.

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", ""]);

let v: Vec<&str> = "A.B:C.D".split_terminator(&['.', ':'][..]).collect();
assert_eq!(v, ["A", "B", "C", "D"]);
1.0.0 ยท source

pub fn rsplit_terminator<'a, P>(&'a self, pat: P) -> RSplitTerminator<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

An iterator over substrings of self, separated by characters matched by a pattern and yielded in reverse order.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

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, the split_terminator method 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"]);

let v: Vec<&str> = "A.B:C.D".rsplit_terminator(&['.', ':'][..]).collect();
assert_eq!(v, ["D", "C", "B", "A"]);
1.0.0 ยท source

pub fn splitn<'a, P>(&'a self, n: usize, pat: P) -> SplitN<'a, P>where P: Pattern<'a>,

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 nth substring) will contain the remainder of the string.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

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.

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"]);
1.0.0 ยท source

pub fn rsplitn<'a, P>(&'a self, n: usize, pat: P) -> RSplitN<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

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 nth substring) will contain the remainder of the string.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

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.

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"]);
1.52.0 ยท source

pub fn split_once<'a, P>(&'a self, delimiter: P) -> Option<(&'a str, &'a str)>where P: Pattern<'a>,

Splits the string on the first occurrence of the specified delimiter and returns prefix before delimiter and suffix after delimiter.

Examples
assert_eq!("cfg".split_once('='), None);
assert_eq!("cfg=".split_once('='), Some(("cfg", "")));
assert_eq!("cfg=foo".split_once('='), Some(("cfg", "foo")));
assert_eq!("cfg=foo=bar".split_once('='), Some(("cfg", "foo=bar")));
1.52.0 ยท source

pub fn rsplit_once<'a, P>(&'a self, delimiter: P) -> Option<(&'a str, &'a str)>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

Splits the string on the last occurrence of the specified delimiter and returns prefix before delimiter and suffix after delimiter.

Examples
assert_eq!("cfg".rsplit_once('='), None);
assert_eq!("cfg=foo".rsplit_once('='), Some(("cfg", "foo")));
assert_eq!("cfg=foo=bar".rsplit_once('='), Some(("cfg=foo", "bar")));
1.2.0 ยท source

pub fn matches<'a, P>(&'a self, pat: P) -> Matches<'a, P>where P: Pattern<'a>,

An iterator over the disjoint matches of a pattern within the given string slice.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

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, e.g., char, but not for &str.

If the pattern allows a reverse search but its results might differ from a forward search, the rmatches method can be used.

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"]);
1.2.0 ยท source

pub fn rmatches<'a, P>(&'a self, pat: P) -> RMatches<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

An iterator over the disjoint matches of a pattern within this string slice, yielded in reverse order.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

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.

For iterating from the front, the matches method can be used.

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"]);
1.5.0 ยท source

pub fn match_indices<'a, P>(&'a self, pat: P) -> MatchIndices<'a, P>where P: Pattern<'a>,

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, a slice of chars, or a function or closure that determines if a character matches.

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, e.g., char, but not for &str.

If the pattern allows a reverse search but its results might differ from a forward search, the rmatch_indices method can be used.

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`
1.5.0 ยท source

pub fn rmatch_indices<'a, P>(&'a self, pat: P) -> RMatchIndices<'a, P>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

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, a slice of chars, or a function or closure that determines if a character matches.

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.

For iterating from the front, the match_indices method can be used.

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`
1.0.0 ยท source

pub fn trim(&self) -> &str

Returns a string slice with leading and trailing whitespace removed.

โ€˜Whitespaceโ€™ is defined according to the terms of the Unicode Derived Core Property White_Space, which includes newlines.

Examples

Basic usage:

let s = "\n Hello\tworld\t\n";

assert_eq!("Hello\tworld", s.trim());
1.30.0 ยท source

pub fn trim_start(&self) -> &str

Returns a string slice with leading whitespace removed.

โ€˜Whitespaceโ€™ is defined according to the terms of the Unicode Derived Core Property White_Space, which includes newlines.

Text directionality

A string is a sequence of bytes. start in this context means the first position of that byte string; for a left-to-right language like English or Russian, this will be left side, and for right-to-left languages like Arabic or Hebrew, this will be the right side.

Examples

Basic usage:

let s = "\n Hello\tworld\t\n";
assert_eq!("Hello\tworld\t\n", s.trim_start());

Directionality:

let s = "  English  ";
assert!(Some('E') == s.trim_start().chars().next());

let s = "  ืขื‘ืจื™ืช  ";
assert!(Some('ืข') == s.trim_start().chars().next());
1.30.0 ยท source

pub fn trim_end(&self) -> &str

Returns a string slice with trailing whitespace removed.

โ€˜Whitespaceโ€™ is defined according to the terms of the Unicode Derived Core Property White_Space, which includes newlines.

Text directionality

A string is a sequence of bytes. end in this context means the last position of that byte string; for a left-to-right language like English or Russian, this will be right side, and for right-to-left languages like Arabic or Hebrew, this will be the left side.

Examples

Basic usage:

let s = "\n Hello\tworld\t\n";
assert_eq!("\n Hello\tworld", s.trim_end());

Directionality:

let s = "  English  ";
assert!(Some('h') == s.trim_end().chars().rev().next());

let s = "  ืขื‘ืจื™ืช  ";
assert!(Some('ืช') == s.trim_end().chars().rev().next());
1.0.0 ยท source

pub fn trim_left(&self) -> &str

๐Ÿ‘ŽDeprecated since 1.33.0: superseded by trim_start

Returns a string slice with leading whitespace removed.

โ€˜Whitespaceโ€™ is defined according to the terms of the Unicode Derived Core Property White_Space.

Text directionality

A string is a sequence of bytes. โ€˜Leftโ€™ in this context means the first position of that byte string; for a language like Arabic or Hebrew which are โ€˜right to leftโ€™ rather than โ€˜left to rightโ€™, 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 = "  ืขื‘ืจื™ืช";
assert!(Some('ืข') == s.trim_left().chars().next());
1.0.0 ยท source

pub fn trim_right(&self) -> &str

๐Ÿ‘ŽDeprecated since 1.33.0: superseded by trim_end

Returns a string slice with trailing whitespace removed.

โ€˜Whitespaceโ€™ is defined according to the terms of the Unicode Derived Core Property White_Space.

Text directionality

A string is a sequence of bytes. โ€˜Rightโ€™ in this context means the last position of that byte string; for a language like Arabic or Hebrew which are โ€˜right to leftโ€™ rather than โ€˜left to rightโ€™, 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 = "ืขื‘ืจื™ืช  ";
assert!(Some('ืช') == s.trim_right().chars().rev().next());
1.0.0 ยท source

pub fn trim_matches<'a, P>(&'a self, pat: P) -> &'a strwhere P: Pattern<'a>, <P as Pattern<'a>>::Searcher: DoubleEndedSearcher<'a>,

Returns a string slice with all prefixes and suffixes that match a pattern repeatedly removed.

The pattern can be a char, a slice of chars, or a function or 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");
1.30.0 ยท source

pub fn trim_start_matches<'a, P>(&'a self, pat: P) -> &'a strwhere P: Pattern<'a>,

Returns a string slice with all prefixes that match a pattern repeatedly removed.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Text directionality

A string is a sequence of bytes. start in this context means the first position of that byte string; for a left-to-right language like English or Russian, this will be left side, and for right-to-left languages like Arabic or Hebrew, this will be the right side.

Examples

Basic usage:

assert_eq!("11foo1bar11".trim_start_matches('1'), "foo1bar11");
assert_eq!("123foo1bar123".trim_start_matches(char::is_numeric), "foo1bar123");

let x: &[_] = &['1', '2'];
assert_eq!("12foo1bar12".trim_start_matches(x), "foo1bar12");
1.45.0 ยท source

pub fn strip_prefix<'a, P>(&'a self, prefix: P) -> Option<&'a str>where P: Pattern<'a>,

Returns a string slice with the prefix removed.

If the string starts with the pattern prefix, returns substring after the prefix, wrapped in Some. Unlike trim_start_matches, this method removes the prefix exactly once.

If the string does not start with prefix, returns None.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples
assert_eq!("foo:bar".strip_prefix("foo:"), Some("bar"));
assert_eq!("foo:bar".strip_prefix("bar"), None);
assert_eq!("foofoo".strip_prefix("foo"), Some("foo"));
1.45.0 ยท source

pub fn strip_suffix<'a, P>(&'a self, suffix: P) -> Option<&'a str>where P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

Returns a string slice with the suffix removed.

If the string ends with the pattern suffix, returns the substring before the suffix, wrapped in Some. Unlike trim_end_matches, this method removes the suffix exactly once.

If the string does not end with suffix, returns None.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Examples
assert_eq!("bar:foo".strip_suffix(":foo"), Some("bar"));
assert_eq!("bar:foo".strip_suffix("bar"), None);
assert_eq!("foofoo".strip_suffix("foo"), Some("foo"));
1.30.0 ยท source

pub fn trim_end_matches<'a, P>(&'a self, pat: P) -> &'a strwhere P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

Returns a string slice with all suffixes that match a pattern repeatedly removed.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Text directionality

A string is a sequence of bytes. end in this context means the last position of that byte string; for a left-to-right language like English or Russian, this will be right side, and for right-to-left languages like Arabic or Hebrew, this will be the left side.

Examples

Simple patterns:

assert_eq!("11foo1bar11".trim_end_matches('1'), "11foo1bar");
assert_eq!("123foo1bar123".trim_end_matches(char::is_numeric), "123foo1bar");

let x: &[_] = &['1', '2'];
assert_eq!("12foo1bar12".trim_end_matches(x), "12foo1bar");

A more complex pattern, using a closure:

assert_eq!("1fooX".trim_end_matches(|c| c == '1' || c == 'X'), "1foo");
1.0.0 ยท source

pub fn trim_left_matches<'a, P>(&'a self, pat: P) -> &'a strwhere P: Pattern<'a>,

๐Ÿ‘ŽDeprecated since 1.33.0: superseded by trim_start_matches

Returns a string slice with all prefixes that match a pattern repeatedly removed.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Text directionality

A string is a sequence of bytes. โ€˜Leftโ€™ in this context means the first position of that byte string; for a language like Arabic or Hebrew which are โ€˜right to leftโ€™ rather than โ€˜left to rightโ€™, 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");
1.0.0 ยท source

pub fn trim_right_matches<'a, P>(&'a self, pat: P) -> &'a strwhere P: Pattern<'a>, <P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,

๐Ÿ‘ŽDeprecated since 1.33.0: superseded by trim_end_matches

Returns a string slice with all suffixes that match a pattern repeatedly removed.

The pattern can be a &str, char, a slice of chars, or a function or closure that determines if a character matches.

Text directionality

A string is a sequence of bytes. โ€˜Rightโ€™ in this context means the last position of that byte string; for a language like Arabic or Hebrew which are โ€˜right to leftโ€™ rather than โ€˜left to rightโ€™, 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");
1.0.0 ยท source

pub fn parse<F>(&self) -> Result<F, <F as FromStr>::Err>where F: FromStr,

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 youโ€™ll see the syntax affectionately known as the โ€˜turbofishโ€™: ::<>. This helps the inference algorithm understand specifically which type youโ€™re trying to parse into.

parse can parse into any type that implements the FromStr trait.

Errors

Will return Err if itโ€™s not possible to parse this string slice into the desired type.

Examples

Basic usage

let four: u32 = "4".parse().unwrap();

assert_eq!(4, four);

Using the โ€˜turbofishโ€™ 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());
1.23.0 ยท source

pub fn is_ascii(&self) -> bool

Checks if all characters in this string are within the ASCII range.

Examples
let ascii = "hello!\n";
let non_ascii = "GrรผรŸe, Jรผrgen โค";

assert!(ascii.is_ascii());
assert!(!non_ascii.is_ascii());
1.23.0 ยท source

pub fn eq_ignore_ascii_case(&self, other: &str) -> bool

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!("Ferrรถs".eq_ignore_ascii_case("FERRรถS"));
assert!(!"Ferrรถs".eq_ignore_ascii_case("FERRร–S"));
1.34.0 ยท source

pub fn escape_debug(&self) -> EscapeDebug<'_>

Return an iterator that escapes each char in self with char::escape_debug.

Note: only extended grapheme codepoints that begin the string will be escaped.

Examples

As an iterator:

for c in "โค\n!".escape_debug() {
    print!("{c}");
}
println!();

Using println! directly:

println!("{}", "โค\n!".escape_debug());

Both are equivalent to:

println!("โค\\n!");

Using to_string:

assert_eq!("โค\n!".escape_debug().to_string(), "โค\\n!");
1.34.0 ยท source

pub fn escape_default(&self) -> EscapeDefault<'_>

Return an iterator that escapes each char in self with char::escape_default.

Examples

As an iterator:

for c in "โค\n!".escape_default() {
    print!("{c}");
}
println!();

Using println! directly:

println!("{}", "โค\n!".escape_default());

Both are equivalent to:

println!("\\u{{2764}}\\n!");

Using to_string:

assert_eq!("โค\n!".escape_default().to_string(), "\\u{2764}\\n!");
1.34.0 ยท source

pub fn escape_unicode(&self) -> EscapeUnicode<'_>

Return an iterator that escapes each char in self with char::escape_unicode.

Examples

As an iterator:

for c in "โค\n!".escape_unicode() {
    print!("{c}");
}
println!();

Using println! directly:

println!("{}", "โค\n!".escape_unicode());

Both are equivalent to:

println!("\\u{{2764}}\\u{{a}}\\u{{21}}");

Using to_string:

assert_eq!("โค\n!".escape_unicode().to_string(), "\\u{2764}\\u{a}\\u{21}");
1.0.0 ยท source

pub fn replace<'a, P>(&'a self, from: P, to: &str) -> Stringwhere P: Pattern<'a>,

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.

Examples

Basic usage:

let s = "this is old";

assert_eq!("this is new", s.replace("old", "new"));
assert_eq!("than an old", s.replace("is", "an"));

When the pattern doesnโ€™t match, it returns this string slice as String:

let s = "this is old";
assert_eq!(s, s.replace("cookie monster", "little lamb"));
1.16.0 ยท source

pub fn replacen<'a, P>(&'a self, pat: P, to: &str, count: usize) -> Stringwhere P: Pattern<'a>,

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.

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 doesnโ€™t match, it returns this string slice as String:

let s = "this is old";
assert_eq!(s, s.replacen("cookie monster", "little lamb", 10));
1.2.0 ยท source

pub fn to_lowercase(&self) -> String

Returns the lowercase equivalent of this string slice, as a new String.

โ€˜Lowercaseโ€™ 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.

Examples

Basic usage:

let s = "HELLO";

assert_eq!("hello", s.to_lowercase());

A tricky example, with sigma:

let sigma = "ฮฃ";

assert_eq!("ฯƒ", sigma.to_lowercase());

// but at the end of a word, it's ฯ‚, not ฯƒ:
let odysseus = "แฝˆฮ”ฮฅฮฃฮฃฮ•ฮŽฮฃ";

assert_eq!("แฝ€ฮดฯ…ฯƒฯƒฮตฯฯ‚", odysseus.to_lowercase());

Languages without case are not changed:

let new_year = "ๅ†œๅŽ†ๆ–ฐๅนด";

assert_eq!(new_year, new_year.to_lowercase());
1.2.0 ยท source

pub fn to_uppercase(&self) -> String

Returns the uppercase equivalent of this string slice, as a new String.

โ€˜Uppercaseโ€™ 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.

Examples

Basic usage:

let s = "hello";

assert_eq!("HELLO", s.to_uppercase());

Scripts without case are not changed:

let new_year = "ๅ†œๅŽ†ๆ–ฐๅนด";

assert_eq!(new_year, new_year.to_uppercase());

One character can become multiple:

let s = "tschรผรŸ";

assert_eq!("TSCHรœSS", s.to_uppercase());
1.16.0 ยท source

pub fn repeat(&self, n: usize) -> String

Creates a new String by repeating a string n times.

Panics

This function will panic if the capacity would overflow.

Examples

Basic usage:

assert_eq!("abc".repeat(4), String::from("abcabcabcabc"));

A panic upon overflow:

โ“˜
// this will panic at runtime
let huge = "0123456789abcdef".repeat(usize::MAX);
1.23.0 ยท source

pub fn to_ascii_uppercase(&self) -> String

Returns a copy of this string where each character is mapped to its ASCII upper case equivalent.

ASCII letters โ€˜aโ€™ to โ€˜zโ€™ are mapped to โ€˜Aโ€™ to โ€˜Zโ€™, 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 = "GrรผรŸe, Jรผrgen โค";

assert_eq!("GRรผรŸE, JรผRGEN โค", s.to_ascii_uppercase());
1.23.0 ยท source

pub fn to_ascii_lowercase(&self) -> String

Returns a copy of this string where each character is mapped to its ASCII lower case equivalent.

ASCII letters โ€˜Aโ€™ to โ€˜Zโ€™ are mapped to โ€˜aโ€™ to โ€˜zโ€™, 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 = "GrรผรŸe, Jรผrgen โค";

assert_eq!("grรผรŸe, jรผrgen โค", s.to_ascii_lowercase());

Trait Implementationsยง

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impl Add<&str> for SharedString

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type Output = SharedString

The resulting type after applying the + operator.
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fn add(self, other: &str) -> SharedString

Performs the + operation. Read more
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impl AddAssign<&str> for SharedString

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fn add_assign(&mut self, other: &str)

Performs the += operation. Read more
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impl AsRef<[u8]> for SharedString

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fn as_ref(&self) -> &[u8] โ“˜

Converts this type into a shared reference of the (usually inferred) input type.
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impl AsRef<CStr> for SharedString

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fn as_ref(&self) -> &CStr

Converts this type into a shared reference of the (usually inferred) input type.
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impl AsRef<str> for SharedString

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fn as_ref(&self) -> &str

Converts this type into a shared reference of the (usually inferred) input type.
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impl Clone for SharedString

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fn clone(&self) -> SharedString

Returns a copy of the value. Read more
1.0.0 ยท sourceยง

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for SharedString

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fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
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impl Default for SharedString

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fn default() -> SharedString

Returns the โ€œdefault valueโ€ for a type. Read more
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impl Deref for SharedString

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type Target = str

The resulting type after dereferencing.
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fn deref(&self) -> &<SharedString as Deref>::Target

Dereferences the value.
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impl Display for SharedString

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fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
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impl From<&SharedString> for String

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fn from(s: &SharedString) -> String

Converts to this type from the input type.
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impl From<&String> for SharedString

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fn from(s: &String) -> SharedString

Converts to this type from the input type.
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impl From<&str> for SharedString

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fn from(value: &str) -> SharedString

Converts to this type from the input type.
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impl From<Key> for SharedString

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fn from(k: Key) -> SharedString

Converts to this type from the input type.
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impl From<SharedString> for StandardListViewItem

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fn from(value: SharedString) -> StandardListViewItem

Converts to this type from the input type.
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impl From<SharedString> for String

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fn from(s: SharedString) -> String

Converts to this type from the input type.
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impl From<String> for SharedString

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fn from(s: String) -> SharedString

Converts to this type from the input type.
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impl From<char> for SharedString

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fn from(c: char) -> SharedString

Converts to this type from the input type.
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impl Hash for SharedString

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fn hash<H>(&self, state: &mut H)where H: Hasher,

Feeds this value into the given Hasher. Read more
1.3.0 ยท sourceยง

fn hash_slice<H>(data: &[Self], state: &mut H)where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl Ord for SharedString

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fn cmp(&self, other: &SharedString) -> Ordering

This method returns an Ordering between self and other. Read more
1.21.0 ยท sourceยง

fn max(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 ยท sourceยง

fn min(self, other: Self) -> Selfwhere Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 ยท sourceยง

fn clamp(self, min: Self, max: Self) -> Selfwhere Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval. Read more
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impl<T> PartialEq<T> for SharedStringwhere T: AsRef<str> + ?Sized,

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fn eq(&self, other: &T) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 ยท sourceยง

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<T> PartialOrd<T> for SharedStringwhere T: AsRef<str> + ?Sized,

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fn partial_cmp(&self, other: &T) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
1.0.0 ยท sourceยง

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
1.0.0 ยท sourceยง

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
1.0.0 ยท sourceยง

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
1.0.0 ยท sourceยง

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl Write for SharedString

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fn write_str(&mut self, s: &str) -> Result<(), Error>

Writes a string slice into this writer, returning whether the write succeeded. Read more
1.1.0 ยท sourceยง

fn write_char(&mut self, c: char) -> Result<(), Error>

Writes a char into this writer, returning whether the write succeeded. Read more
1.0.0 ยท sourceยง

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Glue for usage of the write! macro with implementors of this trait. Read more
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impl Eq for SharedString

Auto Trait Implementationsยง

Blanket Implementationsยง

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

const: unstable ยท sourceยง

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

const: unstable ยท sourceยง

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CallHasher for Twhere T: Hash + ?Sized,

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default fn get_hash<H, B>(value: &H, build_hasher: &B) -> u64where H: Hash + ?Sized, B: BuildHasher,

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impl<T> Downcast for Twhere T: Any,

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fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>

Convert Box<dyn Trait> (where Trait: Downcast) to Box<dyn Any>. Box<dyn Any> can then be further downcast into Box<ConcreteType> where ConcreteType implements Trait.
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fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>

Convert Rc<Trait> (where Trait: Downcast) to Rc<Any>. Rc<Any> can then be further downcast into Rc<ConcreteType> where ConcreteType implements Trait.
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fn as_any(&self) -> &(dyn Any + 'static)

Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Anyโ€™s vtable from &Traitโ€™s.
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fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)

Convert &mut Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &mut Anyโ€™s vtable from &mut Traitโ€™s.
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impl<T> From<T> for T

const: unstable ยท sourceยง

fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

const: unstable ยท sourceยง

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> Pointable for T

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const ALIGN: usize = mem::align_of::<T>()

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<R, P> ReadPrimitive<R> for Pwhere R: Read + ReadEndian<P>, P: Default,

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fn read_from_little_endian(read: &mut R) -> Result<Self, Error>

Read this value from the supplied reader. Same as ReadEndian::read_from_little_endian().
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fn read_from_big_endian(read: &mut R) -> Result<Self, Error>

Read this value from the supplied reader. Same as ReadEndian::read_from_big_endian().
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fn read_from_native_endian(read: &mut R) -> Result<Self, Error>

Read this value from the supplied reader. Same as ReadEndian::read_from_native_endian().
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impl<T> ToOwned for Twhere T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T> ToString for Twhere T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
const: unstable ยท sourceยง

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
const: unstable ยท sourceยง

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.