1.0.0[−]Primitive Type str
String slices.
The str
type, also called a 'string slice', is the most primitive string
type. It is usually seen in its borrowed form, &str
. It is also the type
of string literals, &'static str
.
String slices are always valid UTF-8.
Examples
String literals are string slices:
let hello = "Hello, world!"; // with an explicit type annotation let hello: &'static str = "Hello, world!";Run
They are 'static
because they're stored directly in the final binary, and
so will be valid for the 'static
duration.
Representation
A &str
is made up of two components: a pointer to some bytes, and a
length. You can look at these with the as_ptr
and len
methods:
use std::slice; use std::str; let story = "Once upon a time..."; let ptr = story.as_ptr(); let len = story.len(); // story has nineteen bytes assert_eq!(19, len); // We can re-build a str out of ptr and len. This is all unsafe because // we are responsible for making sure the two components are valid: let s = unsafe { // First, we build a &[u8]... let slice = slice::from_raw_parts(ptr, len); // ... and then convert that slice into a string slice str::from_utf8(slice) }; assert_eq!(s, Ok(story));Run
Note: This example shows the internals of &str
. unsafe
should not be
used to get a string slice under normal circumstances. Use as_slice
instead.
Methods
impl str
[src]
pub fn len(&self) -> usize
[src]
Returns the length of self
.
This length is in bytes, not char
s or graphemes. In other words,
it may not be what a human considers the length of the string.
Examples
Basic usage:
let len = "foo".len(); assert_eq!(3, len); let len = "ƒoo".len(); // fancy f! assert_eq!(4, len);Run
pub fn is_empty(&self) -> bool
[src]
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());Run
pub fn is_char_boundary(&self, index: usize) -> bool
1.9.0[src]
Checks that index
-th byte lies at the start and/or end of a
UTF-8 code point sequence.
The start and end of the string (when index == self.len()
) are
considered to be
boundaries.
Returns false
if index
is greater than self.len()
.
Examples
let s = "Löwe 老虎 Léopard"; assert!(s.is_char_boundary(0)); // start of `老` assert!(s.is_char_boundary(6)); assert!(s.is_char_boundary(s.len())); // second byte of `ö` assert!(!s.is_char_boundary(2)); // third byte of `老` assert!(!s.is_char_boundary(8));Run
pub fn as_bytes(&self) -> &[u8]
[src]
Converts a string slice to a byte slice. To convert the byte slice back
into a string slice, use the str::from_utf8
function.
Examples
Basic usage:
let bytes = "bors".as_bytes(); assert_eq!(b"bors", bytes);Run
pub unsafe fn as_bytes_mut(&mut self) -> &mut [u8]
1.20.0[src]
Converts a mutable string slice to a mutable byte slice. To convert the
mutable byte slice back into a mutable string slice, use the
str::from_utf8_mut
function.
Examples
Basic usage:
let mut s = String::from("Hello"); let bytes = unsafe { s.as_bytes_mut() }; assert_eq!(b"Hello", bytes);Run
Mutability:
let mut s = String::from("🗻∈🌏"); unsafe { let bytes = s.as_bytes_mut(); bytes[0] = 0xF0; bytes[1] = 0x9F; bytes[2] = 0x8D; bytes[3] = 0x94; } assert_eq!("🍔∈🌏", s);Run
pub const fn as_ptr(&self) -> *const u8
[src]
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();Run
pub fn as_mut_ptr(&mut self) -> *mut u8
1.36.0[src]
Converts a mutable 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.
It is your responsibility to make sure that the string slice only gets modified in a way that it remains valid UTF-8.
pub fn get<I>(&self, i: I) -> Option<&<I as SliceIndex<str>>::Output> where
I: SliceIndex<str>,
1.20.0[src]
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("🗻∈🌏"); assert_eq!(Some("🗻"), v.get(0..4)); // indices not on UTF-8 sequence boundaries assert!(v.get(1..).is_none()); assert!(v.get(..8).is_none()); // out of bounds assert!(v.get(..42).is_none());Run
pub fn get_mut<I>(
&mut self,
i: I
) -> Option<&mut <I as SliceIndex<str>>::Output> where
I: SliceIndex<str>,
1.20.0[src]
&mut self,
i: I
) -> Option<&mut <I as SliceIndex<str>>::Output> where
I: SliceIndex<str>,
Returns a mutable subslice of str
.
This is the non-panicking alternative to indexing the str
. Returns
None
whenever equivalent indexing operation would panic.
Examples
let mut v = String::from("hello"); // correct length assert!(v.get_mut(0..5).is_some()); // out of bounds assert!(v.get_mut(..42).is_none()); assert_eq!(Some("he"), v.get_mut(0..2).map(|v| &*v)); assert_eq!("hello", v); { let s = v.get_mut(0..2); let s = s.map(|s| { s.make_ascii_uppercase(); &*s }); assert_eq!(Some("HE"), s); } assert_eq!("HEllo", v);Run
pub unsafe fn get_unchecked<I>(&self, i: I) -> &<I as SliceIndex<str>>::Output where
I: SliceIndex<str>,
1.20.0[src]
I: SliceIndex<str>,
Returns a unchecked subslice of str
.
This is the unchecked alternative to indexing the str
.
Safety
Callers of this function are responsible that these preconditions are satisfied:
- The starting index must come before the ending index;
- Indexes must be within bounds of the original slice;
- Indexes must lie on UTF-8 sequence boundaries.
Failing that, the returned string slice may reference invalid memory or
violate the invariants communicated by the str
type.
Examples
let v = "🗻∈🌏"; unsafe { assert_eq!("🗻", v.get_unchecked(0..4)); assert_eq!("∈", v.get_unchecked(4..7)); assert_eq!("🌏", v.get_unchecked(7..11)); }Run
pub unsafe fn get_unchecked_mut<I>(
&mut self,
i: I
) -> &mut <I as SliceIndex<str>>::Output where
I: SliceIndex<str>,
1.20.0[src]
&mut self,
i: I
) -> &mut <I as SliceIndex<str>>::Output where
I: SliceIndex<str>,
Returns a mutable, unchecked subslice of str
.
This is the unchecked alternative to indexing the str
.
Safety
Callers of this function are responsible that these preconditions are satisfied:
- The starting index must come before the ending index;
- Indexes must be within bounds of the original slice;
- Indexes must lie on UTF-8 sequence boundaries.
Failing that, the returned string slice may reference invalid memory or
violate the invariants communicated by the str
type.
Examples
let mut v = String::from("🗻∈🌏"); unsafe { assert_eq!("🗻", v.get_unchecked_mut(0..4)); assert_eq!("∈", v.get_unchecked_mut(4..7)); assert_eq!("🌏", v.get_unchecked_mut(7..11)); }Run
pub unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str
[src]
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 come beforeend
.begin
andend
must be byte positions within the string slice.begin
andend
must lie on UTF-8 sequence boundaries.
Examples
Basic usage:
let s = "Löwe 老虎 Léopard"; unsafe { assert_eq!("Löwe 老虎 Léopard", s.slice_unchecked(0, 21)); } let s = "Hello, world!"; unsafe { assert_eq!("world", s.slice_unchecked(7, 12)); }Run
pub unsafe fn slice_mut_unchecked(
&mut self,
begin: usize,
end: usize
) -> &mut str
1.5.0[src]
&mut self,
begin: usize,
end: usize
) -> &mut str
use get_unchecked_mut(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 IndexMut
.
This new slice goes from begin
to end
, including begin
but
excluding end
.
To get an immutable string slice instead, see the
slice_unchecked
method.
Safety
Callers of this function are responsible that three preconditions are satisfied:
begin
must come beforeend
.begin
andend
must be byte positions within the string slice.begin
andend
must lie on UTF-8 sequence boundaries.
pub fn split_at(&self, mid: usize) -> (&str, &str)
1.4.0[src]
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
beyond the last code point of the string slice.
Examples
Basic usage:
let s = "Per Martin-Löf"; let (first, last) = s.split_at(3); assert_eq!("Per", first); assert_eq!(" Martin-Löf", last);Run
pub fn split_at_mut(&mut self, mid: usize) -> (&mut str, &mut str)
1.4.0[src]
Divide one mutable string slice into two at an index.
The argument, mid
, should be a byte offset from the start of the
string. It must also be on the boundary of a UTF-8 code point.
The two slices returned go from the start of the string slice to mid
,
and from mid
to the end of the string slice.
To get immutable string slices instead, see the split_at
method.
Panics
Panics if mid
is not on a UTF-8 code point boundary, or if it is
beyond the last code point of the string slice.
Examples
Basic usage:
let mut s = "Per Martin-Löf".to_string(); { let (first, last) = s.split_at_mut(3); first.make_ascii_uppercase(); assert_eq!("PER", first); assert_eq!(" Martin-Löf", last); } assert_eq!("PER Martin-Löf", s);Run
ⓘImportant traits for Chars<'a>pub fn chars(&self) -> Chars
[src]
Returns an iterator over the char
s of a string slice.
As a string slice consists of valid UTF-8, we can iterate through a
string slice by char
. This method returns such an iterator.
It's important to remember that char
represents a Unicode Scalar
Value, and may not match your idea of what a 'character' is. Iteration
over grapheme clusters may be what you actually want.
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());Run
Remember, char
s may not match your human intuition about characters:
let y = "y̆"; let mut chars = y.chars(); assert_eq!(Some('y'), chars.next()); // not 'y̆' assert_eq!(Some('\u{0306}'), chars.next()); assert_eq!(None, chars.next());Run
ⓘImportant traits for CharIndices<'a>pub fn char_indices(&self) -> CharIndices
[src]
Returns an iterator over the char
s of a string slice, and their
positions.
As a string slice consists of valid UTF-8, we can iterate through a
string slice by char
. This method returns an iterator of both
these char
s, as well as their byte positions.
The iterator yields tuples. The position is first, the char
is
second.
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());Run
Remember, char
s may not match your human intuition about characters:
let yes = "y̆es"; let mut char_indices = yes.char_indices(); assert_eq!(Some((0, 'y')), char_indices.next()); // not (0, 'y̆') assert_eq!(Some((1, '\u{0306}')), char_indices.next()); // note the 3 here - the last character took up two bytes assert_eq!(Some((3, 'e')), char_indices.next()); assert_eq!(Some((4, 's')), char_indices.next()); assert_eq!(None, char_indices.next());Run
ⓘImportant traits for Bytes<'_>pub fn bytes(&self) -> Bytes
[src]
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());Run
ⓘImportant traits for SplitWhitespace<'a>pub fn split_whitespace(&self) -> SplitWhitespace
1.1.0[src]
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.
'Whitespace' 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());Run
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());Run
ⓘImportant traits for SplitAsciiWhitespace<'a>pub fn split_ascii_whitespace(&self) -> SplitAsciiWhitespace
1.34.0[src]
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());Run
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());Run
ⓘImportant traits for Lines<'a>pub fn lines(&self) -> Lines
[src]
An iterator over the lines of a string, as string slices.
Lines are ended with either a newline (\n
) or a carriage return with
a line feed (\r\n
).
The final line ending is optional.
Examples
Basic usage:
let text = "foo\r\nbar\n\nbaz\n"; let mut lines = text.lines(); assert_eq!(Some("foo"), lines.next()); assert_eq!(Some("bar"), lines.next()); assert_eq!(Some(""), lines.next()); assert_eq!(Some("baz"), lines.next()); assert_eq!(None, lines.next());Run
The final line ending isn't required:
let text = "foo\nbar\n\r\nbaz"; let mut lines = text.lines(); assert_eq!(Some("foo"), lines.next()); assert_eq!(Some("bar"), lines.next()); assert_eq!(Some(""), lines.next()); assert_eq!(Some("baz"), lines.next()); assert_eq!(None, lines.next());Run
ⓘImportant traits for LinesAny<'a>pub fn lines_any(&self) -> LinesAny
[src]
use lines() instead now
An iterator over the lines of a string.
ⓘImportant traits for EncodeUtf16<'a>pub fn encode_utf16(&self) -> EncodeUtf16
1.8.0[src]
Returns an iterator of u16
over the string encoded as UTF-16.
Examples
Basic usage:
let text = "Zażółć gęślą jaźń"; let utf8_len = text.len(); let utf16_len = text.encode_utf16().count(); assert!(utf16_len <= utf8_len);Run
pub fn contains<'a, P>(&'a self, pat: P) -> bool where
P: Pattern<'a>,
[src]
P: Pattern<'a>,
Returns true
if the given pattern matches a sub-slice of
this string slice.
Returns false
if it does not.
Examples
Basic usage:
let bananas = "bananas"; assert!(bananas.contains("nana")); assert!(!bananas.contains("apples"));Run
pub fn starts_with<'a, P>(&'a self, pat: P) -> bool where
P: Pattern<'a>,
[src]
P: Pattern<'a>,
Returns true
if the given pattern matches a prefix of this
string slice.
Returns false
if it does not.
Examples
Basic usage:
let bananas = "bananas"; assert!(bananas.starts_with("bana")); assert!(!bananas.starts_with("nana"));Run
pub fn ends_with<'a, P>(&'a self, pat: P) -> bool where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
[src]
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.
Examples
Basic usage:
let bananas = "bananas"; assert!(bananas.ends_with("anas")); assert!(!bananas.ends_with("nana"));Run
pub fn find<'a, P>(&'a self, pat: P) -> Option<usize> where
P: Pattern<'a>,
[src]
P: Pattern<'a>,
Returns the byte index of the first character of this string slice that matches the pattern.
Returns None
if the pattern doesn't match.
The pattern can be a &str
, char
, or a closure that determines if
a character matches.
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));Run
More complex patterns using point-free style and closures:
let s = "Löwe 老虎 Léopard"; assert_eq!(s.find(char::is_whitespace), Some(5)); assert_eq!(s.find(char::is_lowercase), Some(1)); assert_eq!(s.find(|c: char| c.is_whitespace() || c.is_lowercase()), Some(1)); assert_eq!(s.find(|c: char| (c < 'o') && (c > 'a')), Some(4));Run
Not finding the pattern:
let s = "Löwe 老虎 Léopard"; let x: &[_] = &['1', '2']; assert_eq!(s.find(x), None);Run
pub fn rfind<'a, P>(&'a self, pat: P) -> Option<usize> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
[src]
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
Returns the byte index of the last character of this string slice that matches the pattern.
Returns None
if the pattern doesn't match.
The pattern can be a &str
, char
, or a closure that determines if
a character matches.
Examples
Simple patterns:
let s = "Löwe 老虎 Léopard"; assert_eq!(s.rfind('L'), Some(13)); assert_eq!(s.rfind('é'), Some(14));Run
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));Run
Not finding the pattern:
let s = "Löwe 老虎 Léopard"; let x: &[_] = &['1', '2']; assert_eq!(s.rfind(x), None);Run
ⓘImportant traits for Split<'a, P>pub fn split<'a, P>(&'a self, pat: P) -> Split<'a, P> where
P: Pattern<'a>,
[src]
P: Pattern<'a>,
An iterator over substrings of this string slice, separated by characters matched by a pattern.
The pattern can be any type that implements the Pattern trait. Notable
examples are &str
, char
, and closures that determines the split.
Iterator behavior
The returned iterator will be a DoubleEndedIterator
if the pattern
allows a reverse search and forward/reverse search yields the same
elements. This is true for, 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"]);Run
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"]);Run
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"]);Run
Contiguous separators are separated by the empty string.
let x = "(///)".to_string(); let d: Vec<_> = x.split('/').collect(); assert_eq!(d, &["(", "", "", ")"]);Run
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", ""]);Run
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", ""]);Run
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"]);Run
It does not give you:
assert_eq!(d, &["a", "b", "c"]);Run
Use split_whitespace
for this behavior.
ⓘImportant traits for RSplit<'a, P>pub fn rsplit<'a, P>(&'a self, pat: P) -> RSplit<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
[src]
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 any type that implements the Pattern trait. Notable
examples are &str
, char
, and closures that determines the split.
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"]);Run
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"]);Run
ⓘImportant traits for SplitTerminator<'a, P>pub fn split_terminator<'a, P>(&'a self, pat: P) -> SplitTerminator<'a, P> where
P: Pattern<'a>,
[src]
P: Pattern<'a>,
An iterator over substrings of the given string slice, separated by characters matched by a pattern.
The pattern can be any type that implements the Pattern trait. Notable
examples are &str
, char
, and closures that determines the split.
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", ""]);Run
ⓘImportant traits for RSplitTerminator<'a, P>pub fn rsplit_terminator<'a, P>(&'a self, pat: P) -> RSplitTerminator<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
[src]
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 any type that implements the Pattern trait. Notable
examples are &str
, char
, and closures 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, 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"]);Run
ⓘImportant traits for SplitN<'a, P>pub fn splitn<'a, P>(&'a self, n: usize, pat: P) -> SplitN<'a, P> where
P: Pattern<'a>,
[src]
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 n
th substring)
will contain the remainder of the string.
The pattern can be any type that implements the Pattern trait. Notable
examples are &str
, char
, and closures that determines the split.
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, [""]);Run
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"]);Run
ⓘImportant traits for RSplitN<'a, P>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>,
[src]
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 n
th substring)
will contain the remainder of the string.
The pattern can be any type that implements the Pattern trait. Notable
examples are &str
, char
, and closures that determines the split.
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"]);Run
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"]);Run
ⓘImportant traits for Matches<'a, P>pub fn matches<'a, P>(&'a self, pat: P) -> Matches<'a, P> where
P: Pattern<'a>,
1.2.0[src]
P: Pattern<'a>,
An iterator over the disjoint matches of a pattern within the given string slice.
The pattern can be any type that implements the Pattern trait. Notable
examples are &str
, char
, and closures that determines the split.
Iterator behavior
The returned iterator will be a DoubleEndedIterator
if the pattern
allows a reverse search and forward/reverse search yields the same
elements. This is true for, 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"]);Run
ⓘImportant traits for RMatches<'a, P>pub fn rmatches<'a, P>(&'a self, pat: P) -> RMatches<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
1.2.0[src]
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
, or a 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"]);Run
ⓘImportant traits for MatchIndices<'a, P>pub fn match_indices<'a, P>(&'a self, pat: P) -> MatchIndices<'a, P> where
P: Pattern<'a>,
1.5.0[src]
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
, or a 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`Run
ⓘImportant traits for RMatchIndices<'a, P>pub fn rmatch_indices<'a, P>(&'a self, pat: P) -> RMatchIndices<'a, P> where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
1.5.0[src]
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
, or a 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`Run
#[must_use = "this returns the trimmed string as a slice, without modifying the original"]
pub fn trim(&self) -> &str
[src]
Returns a string slice with leading and trailing whitespace removed.
'Whitespace' is defined according to the terms of the Unicode Derived
Core Property White_Space
.
Examples
Basic usage:
let s = " Hello\tworld\t"; assert_eq!("Hello\tworld", s.trim());Run
#[must_use = "this returns the trimmed string as a new slice, without modifying the original"]
pub fn trim_start(&self) -> &str
1.30.0[src]
Returns a string slice with leading whitespace removed.
'Whitespace' is defined according to the terms of the Unicode Derived
Core Property White_Space
.
Text directionality
A string is a sequence of bytes. 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
like Arabic or Hebrew, this will be the right side.
Examples
Basic usage:
let s = " Hello\tworld\t"; assert_eq!("Hello\tworld\t", s.trim_start());Run
Directionality:
let s = " English "; assert!(Some('E') == s.trim_start().chars().next()); let s = " עברית "; assert!(Some('ע') == s.trim_start().chars().next());Run
#[must_use = "this returns the trimmed string as a new slice, without modifying the original"]
pub fn trim_end(&self) -> &str
1.30.0[src]
Returns a string slice with trailing whitespace removed.
'Whitespace' is defined according to the terms of the Unicode Derived
Core Property White_Space
.
Text directionality
A string is a sequence of bytes. 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
like Arabic or Hebrew, this will be the left side.
Examples
Basic usage:
let s = " Hello\tworld\t"; assert_eq!(" Hello\tworld", s.trim_end());Run
Directionality:
let s = " English "; assert!(Some('h') == s.trim_end().chars().rev().next()); let s = " עברית "; assert!(Some('ת') == s.trim_end().chars().rev().next());Run
pub fn trim_left(&self) -> &str
[src]
superseded by trim_start
Returns a string slice with leading whitespace removed.
'Whitespace' is defined according to the terms of the Unicode Derived
Core Property White_Space
.
Text directionality
A string is a sequence of bytes. 'Left' in this context means the first position of that byte string; for a language like Arabic or Hebrew which are 'right to left' rather than 'left to right', this will be the right side, not the left.
Examples
Basic usage:
let s = " Hello\tworld\t"; assert_eq!("Hello\tworld\t", s.trim_left());Run
Directionality:
let s = " English"; assert!(Some('E') == s.trim_left().chars().next()); let s = " עברית"; assert!(Some('ע') == s.trim_left().chars().next());Run
pub fn trim_right(&self) -> &str
[src]
superseded by trim_end
Returns a string slice with trailing whitespace removed.
'Whitespace' is defined according to the terms of the Unicode Derived
Core Property White_Space
.
Text directionality
A string is a sequence of bytes. 'Right' in this context means the last position of that byte string; for a language like Arabic or Hebrew which are 'right to left' rather than 'left to right', this will be the left side, not the right.
Examples
Basic usage:
let s = " Hello\tworld\t"; assert_eq!(" Hello\tworld", s.trim_right());Run
Directionality:
let s = "English "; assert!(Some('h') == s.trim_right().chars().rev().next()); let s = "עברית "; assert!(Some('ת') == s.trim_right().chars().rev().next());Run
#[must_use = "this returns the trimmed string as a new slice, without modifying the original"]
pub fn trim_matches<'a, P>(&'a self, pat: P) -> &'a str where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: DoubleEndedSearcher<'a>,
[src]
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
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");Run
A more complex pattern, using a closure:
assert_eq!("1foo1barXX".trim_matches(|c| c == '1' || c == 'X'), "foo1bar");Run
#[must_use = "this returns the trimmed string as a new slice, without modifying the original"]
pub fn trim_start_matches<'a, P>(&'a self, pat: P) -> &'a str where
P: Pattern<'a>,
1.30.0[src]
P: Pattern<'a>,
Returns a string slice with all prefixes that match a pattern repeatedly removed.
The pattern can be a &str
, char
, or a closure that determines if
a character matches.
Text directionality
A string is a sequence of bytes. 'Left' in this context means the first position of that byte string; for a language like Arabic or Hebrew which are 'right to left' rather than 'left to right', this will be the right side, not the left.
Examples
Basic usage:
assert_eq!("11foo1bar11".trim_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");Run
#[must_use = "this returns the trimmed string as a new slice, without modifying the original"]
pub fn trim_end_matches<'a, P>(&'a self, pat: P) -> &'a str where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
1.30.0[src]
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
, or a closure that
determines if a character matches.
Text directionality
A string is a sequence of bytes. 'Right' in this context means the last position of that byte string; for a language like Arabic or Hebrew which are 'right to left' rather than 'left to right', this will be the left side, not the right.
Examples
Simple patterns:
assert_eq!("11foo1bar11".trim_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");Run
A more complex pattern, using a closure:
assert_eq!("1fooX".trim_end_matches(|c| c == '1' || c == 'X'), "1foo");Run
pub fn trim_left_matches<'a, P>(&'a self, pat: P) -> &'a str where
P: Pattern<'a>,
[src]
P: Pattern<'a>,
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
, or a 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
like Arabic or Hebrew, this will be the right side.
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");Run
pub fn trim_right_matches<'a, P>(&'a self, pat: P) -> &'a str where
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
[src]
P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
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
, or a 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
like Arabic or Hebrew, this will be the left side.
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");Run
A more complex pattern, using a closure:
assert_eq!("1fooX".trim_right_matches(|c| c == '1' || c == 'X'), "1foo");Run
pub fn parse<F>(&self) -> Result<F, <F as FromStr>::Err> where
F: FromStr,
[src]
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 you'll see
the syntax affectionately known as the 'turbofish': ::<>
. This
helps the inference algorithm understand specifically which type
you're trying to parse into.
parse
can parse any type that implements the FromStr
trait.
Errors
Will return Err
if it'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);Run
Using the 'turbofish' instead of annotating four
:
let four = "4".parse::<u32>(); assert_eq!(Ok(4), four);Run
Failing to parse:
let nope = "j".parse::<u32>(); assert!(nope.is_err());Run
pub fn is_ascii(&self) -> bool
1.23.0[src]
Checks if all characters in this string are within the ASCII range.
Examples
let ascii = "hello!\n"; let non_ascii = "Grüße, Jürgen ❤"; assert!(ascii.is_ascii()); assert!(!non_ascii.is_ascii());Run
pub fn eq_ignore_ascii_case(&self, other: &str) -> bool
1.23.0[src]
Checks that two strings are an ASCII case-insensitive match.
Same as to_ascii_lowercase(a) == to_ascii_lowercase(b)
,
but without allocating and copying temporaries.
Examples
assert!("Ferris".eq_ignore_ascii_case("FERRIS")); assert!("Ferrös".eq_ignore_ascii_case("FERRöS")); assert!(!"Ferrös".eq_ignore_ascii_case("FERRÖS"));Run
pub fn make_ascii_uppercase(&mut self)
1.23.0[src]
Converts this string to its ASCII upper case equivalent in-place.
ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', but non-ASCII letters are unchanged.
To return a new uppercased value without modifying the existing one, use
to_ascii_uppercase
.
pub fn make_ascii_lowercase(&mut self)
1.23.0[src]
Converts this string to its ASCII lower case equivalent in-place.
ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', but non-ASCII letters are unchanged.
To return a new lowercased value without modifying the existing one, use
to_ascii_lowercase
.
ⓘImportant traits for EscapeDebug<'a>pub fn escape_debug(&self) -> EscapeDebug
1.34.0[src]
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 "❤\n!".escape_debug() { print!("{}", c); } println!();Run
Using println!
directly:
println!("{}", "❤\n!".escape_debug());Run
Both are equivalent to:
println!("❤\\n!");Run
Using to_string
:
assert_eq!("❤\n!".escape_debug().to_string(), "❤\\n!");Run
ⓘImportant traits for EscapeDefault<'a>pub fn escape_default(&self) -> EscapeDefault
1.34.0[src]
Return an iterator that escapes each char in self
with char::escape_default
.
Examples
As an iterator:
for c in "❤\n!".escape_default() { print!("{}", c); } println!();Run
Using println!
directly:
println!("{}", "❤\n!".escape_default());Run
Both are equivalent to:
println!("\\u{{2764}}\\n!");Run
Using to_string
:
assert_eq!("❤\n!".escape_default().to_string(), "\\u{2764}\\n!");Run
ⓘImportant traits for EscapeUnicode<'a>pub fn escape_unicode(&self) -> EscapeUnicode
1.34.0[src]
Return an iterator that escapes each char in self
with char::escape_unicode
.
Examples
As an iterator:
for c in "❤\n!".escape_unicode() { print!("{}", c); } println!();Run
Using println!
directly:
println!("{}", "❤\n!".escape_unicode());Run
Both are equivalent to:
println!("\\u{{2764}}\\u{{a}}\\u{{21}}");Run
Using to_string
:
assert_eq!("❤\n!".escape_unicode().to_string(), "\\u{2764}\\u{a}\\u{21}");Run
impl str
[src]
Methods for string slices.
ⓘImportant traits for Box<I>pub fn into_boxed_bytes(self: Box<str>) -> Box<[u8]>
1.20.0[src]
Converts a Box<str>
into a Box<[u8]>
without copying or allocating.
Examples
Basic usage:
let s = "this is a string"; let boxed_str = s.to_owned().into_boxed_str(); let boxed_bytes = boxed_str.into_boxed_bytes(); assert_eq!(*boxed_bytes, *s.as_bytes());Run
#[must_use = "this returns the replaced string as a new allocation, without modifying the original"]
pub fn replace<'a, P>(&'a self, from: P, to: &str) -> String where
P: Pattern<'a>,
[src]
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"));Run
When the pattern doesn't match:
let s = "this is old"; assert_eq!(s, s.replace("cookie monster", "little lamb"));Run
#[must_use = "this returns the replaced string as a new allocation, without modifying the original"]
pub fn replacen<'a, P>(&'a self, pat: P, to: &str, count: usize) -> String where
P: Pattern<'a>,
1.16.0[src]
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));Run
When the pattern doesn't match:
let s = "this is old"; assert_eq!(s, s.replacen("cookie monster", "little lamb", 10));Run
pub fn to_lowercase(&self) -> String
1.2.0[src]
Returns the lowercase equivalent of this string slice, as a new String
.
'Lowercase' is defined according to the terms of the Unicode Derived Core Property
Lowercase
.
Since some characters can expand into multiple characters when changing
the case, this function returns a String
instead of modifying the
parameter in-place.
Examples
Basic usage:
let s = "HELLO"; assert_eq!("hello", s.to_lowercase());Run
A tricky example, with sigma:
let sigma = "Σ"; assert_eq!("σ", sigma.to_lowercase()); // but at the end of a word, it's ς, not σ: let odysseus = "ὈΔΥΣΣΕΎΣ"; assert_eq!("ὀδυσσεύς", odysseus.to_lowercase());Run
Languages without case are not changed:
let new_year = "农历新年"; assert_eq!(new_year, new_year.to_lowercase());Run
pub fn to_uppercase(&self) -> String
1.2.0[src]
Returns the uppercase equivalent of this string slice, as a new String
.
'Uppercase' is defined according to the terms of the Unicode Derived Core Property
Uppercase
.
Since some characters can expand into multiple characters when changing
the case, this function returns a String
instead of modifying the
parameter in-place.
Examples
Basic usage:
let s = "hello"; assert_eq!("HELLO", s.to_uppercase());Run
Scripts without case are not changed:
let new_year = "农历新年"; assert_eq!(new_year, new_year.to_uppercase());Run
pub fn into_string(self: Box<str>) -> String
1.4.0[src]
Converts a Box<str>
into a String
without copying or allocating.
Examples
Basic usage:
let string = String::from("birthday gift"); let boxed_str = string.clone().into_boxed_str(); assert_eq!(boxed_str.into_string(), string);Run
pub fn repeat(&self, n: usize) -> String
1.16.0[src]
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"));Run
A panic upon overflow:
fn main() { // this will panic at runtime "0123456789abcdef".repeat(usize::max_value()); }Run
pub fn to_ascii_uppercase(&self) -> String
1.23.0[src]
Returns a copy of this string where each character is mapped to its ASCII upper case equivalent.
ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', but non-ASCII letters are unchanged.
To uppercase the value in-place, use make_ascii_uppercase
.
To uppercase ASCII characters in addition to non-ASCII characters, use
to_uppercase
.
Examples
let s = "Grüße, Jürgen ❤"; assert_eq!("GRüßE, JüRGEN ❤", s.to_ascii_uppercase());Run
pub fn to_ascii_lowercase(&self) -> String
1.23.0[src]
Returns a copy of this string where each character is mapped to its ASCII lower case equivalent.
ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', but non-ASCII letters are unchanged.
To lowercase the value in-place, use make_ascii_lowercase
.
To lowercase ASCII characters in addition to non-ASCII characters, use
to_lowercase
.
Examples
let s = "Grüße, Jürgen ❤"; assert_eq!("grüße, jürgen ❤", s.to_ascii_lowercase());Run
Trait Implementations
impl PartialOrd<str> for str
[src]
Implements comparison operations on strings.
Strings are compared lexicographically by their byte values. This compares Unicode code
points based on their positions in the code charts. This is not necessarily the same as
"alphabetical" order, which varies by language and locale. Comparing strings according to
culturally-accepted standards requires locale-specific data that is outside the scope of
the str
type.
fn partial_cmp(&self, other: &str) -> Option<Ordering>
[src]
#[must_use]
fn lt(&self, other: &Rhs) -> bool
[src]
This method tests less than (for self
and other
) and is used by the <
operator. Read more
#[must_use]
fn le(&self, other: &Rhs) -> bool
[src]
This method tests less than or equal to (for self
and other
) and is used by the <=
operator. Read more
#[must_use]
fn gt(&self, other: &Rhs) -> bool
[src]
This method tests greater than (for self
and other
) and is used by the >
operator. Read more
#[must_use]
fn ge(&self, other: &Rhs) -> bool
[src]
This method tests greater than or equal to (for self
and other
) and is used by the >=
operator. Read more
impl Hash for str
[src]
fn hash<H>(&self, state: &mut H) where
H: Hasher,
[src]
H: Hasher,
fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
1.3.0[src]
H: Hasher,
Feeds a slice of this type into the given [Hasher
]. Read more
impl<'_> Default for &'_ mut str
1.28.0[src]
impl<'_> Default for &'_ str
[src]
impl Eq for str
[src]
impl<I> IndexMut<I> for str where
I: SliceIndex<str>,
[src]
I: SliceIndex<str>,
fn index_mut(&mut self, index: I) -> &mut <I as SliceIndex<str>>::Output
[src]
impl AsRef<str> for str
[src]
impl AsRef<[u8]> for str
[src]
impl Debug for str
[src]
impl<'a, 'b> Pattern<'a> for &'b str
[src]
Non-allocating substring search.
Will handle the pattern ""
as returning empty matches at each character
boundary.
type Searcher = StrSearcher<'a, 'b>
🔬 This is a nightly-only experimental API. (pattern
#27721)
API not fully fleshed out and ready to be stabilized
Associated searcher for this pattern
fn into_searcher(self, haystack: &'a str) -> StrSearcher<'a, 'b>
[src]
fn is_prefix_of(self, haystack: &'a str) -> bool
[src]
🔬 This is a nightly-only experimental API. (pattern
#27721)
API not fully fleshed out and ready to be stabilized
Checks whether the pattern matches at the front of the haystack
fn is_suffix_of(self, haystack: &'a str) -> bool
[src]
🔬 This is a nightly-only experimental API. (pattern
#27721)
API not fully fleshed out and ready to be stabilized
Checks whether the pattern matches at the back of the haystack
fn is_contained_in(self, haystack: &'a str) -> bool
[src]
🔬 This is a nightly-only experimental API. (pattern
#27721)
API not fully fleshed out and ready to be stabilized
Checks whether the pattern matches anywhere in the haystack
impl Ord for str
[src]
Implements ordering of strings.
Strings are ordered lexicographically by their byte values. This orders Unicode code
points based on their positions in the code charts. This is not necessarily the same as
"alphabetical" order, which varies by language and locale. Sorting strings according to
culturally-accepted standards requires locale-specific data that is outside the scope of
the str
type.
fn cmp(&self, other: &str) -> Ordering
[src]
fn max(self, other: Self) -> Self
1.21.0[src]
Compares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self
1.21.0[src]
Compares and returns the minimum of two values. Read more
fn clamp(self, min: Self, max: Self) -> Self
[src]
Restrict a value to a certain interval. Read more
impl<I> Index<I> for str where
I: SliceIndex<str>,
[src]
I: SliceIndex<str>,
type Output = <I as SliceIndex<str>>::Output
The returned type after indexing.
fn index(&self, index: I) -> &<I as SliceIndex<str>>::Output
[src]
impl PartialEq<str> for str
[src]
impl Display for str
[src]
impl<'a, 'b> PartialEq<String> for str
[src]
impl<'a, 'b> PartialEq<String> for &'a str
[src]
impl<'a, 'b> PartialEq<Cow<'a, str>> for &'b str
[src]
impl<'a, 'b> PartialEq<Cow<'a, str>> for str
[src]
impl ToOwned for str
[src]
type Owned = String
The resulting type after obtaining ownership.
fn to_owned(&self) -> String
[src]
fn clone_into(&self, target: &mut String)
[src]
impl ToString for str
1.9.0[src]
impl AsciiExt for str
[src]
type Owned = String
use inherent methods instead
Container type for copied ASCII characters.
fn is_ascii(&self) -> bool
[src]
fn to_ascii_uppercase(&self) -> Self::Owned
[src]
fn to_ascii_lowercase(&self) -> Self::Owned
[src]
fn eq_ignore_ascii_case(&self, o: &Self) -> bool
[src]
fn make_ascii_uppercase(&mut self)
[src]
fn make_ascii_lowercase(&mut self)
[src]
impl ToSocketAddrs for str
[src]
type Iter = IntoIter<SocketAddr>
Returned iterator over socket addresses which this type may correspond to. Read more
fn to_socket_addrs(&self) -> Result<IntoIter<SocketAddr>>
[src]
impl PartialEq<OsString> for str
[src]
fn eq(&self, other: &OsString) -> bool
[src]
#[must_use]
fn ne(&self, other: &Rhs) -> bool
[src]
This method tests for !=
.
impl<'a> PartialEq<OsString> for &'a str
1.29.0[src]
fn eq(&self, other: &OsString) -> bool
[src]
#[must_use]
fn ne(&self, other: &Rhs) -> bool
[src]
This method tests for !=
.
impl PartialEq<OsStr> for str
[src]
fn eq(&self, other: &OsStr) -> bool
[src]
#[must_use]
fn ne(&self, other: &Rhs) -> bool
[src]
This method tests for !=
.
impl AsRef<OsStr> for str
[src]
impl AsRef<Path> for str
[src]
Auto Trait Implementations
Blanket Implementations
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
T: ?Sized,
ⓘImportant traits for &'_ mut Ffn borrow_mut(&mut self) -> &mut T
[src]
impl<T> Any for T where
T: 'static + ?Sized,
[src]
T: 'static + ?Sized,
impl<T> ToOwned for T where
T: Clone,
[src]
T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
[src]
fn clone_into(&self, target: &mut T)
[src]
impl<T> ToString for T where
T: Display + ?Sized,
[src]
T: Display + ?Sized,