Struct rustc_data_structures::base_n::BaseNString
source · pub struct BaseNString {
start: usize,
buf: [Char; 128],
}
Fields§
§start: usize
§buf: [Char; 128]
Methods from Deref<Target = str>§
1.0.0 · sourcepub fn is_empty(&self) -> bool
pub fn is_empty(&self) -> bool
Returns true
if self
has a length of zero bytes.
§Examples
let s = "";
assert!(s.is_empty());
let s = "not empty";
assert!(!s.is_empty());
1.9.0 · sourcepub fn is_char_boundary(&self, index: usize) -> bool
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 = "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));
sourcepub fn floor_char_boundary(&self, index: usize) -> usize
🔬This is a nightly-only experimental API. (round_char_boundary
)
pub fn floor_char_boundary(&self, index: usize) -> usize
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 it’s still valid UTF-8, but doesn’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 aren’t split. For example, the emoji 🧑🔬 (scientist) could be split so that the string only includes 🧑 (person) instead.
§Examples
#![feature(round_char_boundary)]
let s = "❤️🧡💛💚💙💜";
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], "❤️🧡");
sourcepub fn ceil_char_boundary(&self, index: usize) -> usize
🔬This is a nightly-only experimental API. (round_char_boundary
)
pub fn ceil_char_boundary(&self, index: usize) -> usize
round_char_boundary
)Finds the closest x
not below index
where is_char_boundary(x)
is true
.
If index
is greater than the length of the string, this returns the length of the string.
This method is the natural complement to floor_char_boundary
. See that method
for more details.
§Examples
#![feature(round_char_boundary)]
let s = "❤️🧡💛💚💙💜";
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], "❤️🧡💛");
1.0.0 · sourcepub fn as_ptr(&self) -> *const u8
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
let s = "Hello";
let ptr = s.as_ptr();
1.20.0 · sourcepub fn get<I>(&self, i: I) -> Option<&<I as SliceIndex<str>>::Output>where
I: SliceIndex<str>,
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("🗻∈🌏");
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());
1.20.0 · sourcepub unsafe fn get_unchecked<I>(&self, i: I) -> &<I as SliceIndex<str>>::Outputwhere
I: SliceIndex<str>,
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 = "🗻∈🌏";
unsafe {
assert_eq!("🗻", v.get_unchecked(0..4));
assert_eq!("∈", v.get_unchecked(4..7));
assert_eq!("🌏", v.get_unchecked(7..11));
}
1.0.0 · sourcepub unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str
👎Deprecated since 1.29.0: use get_unchecked(begin..end)
instead
pub unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str
get_unchecked(begin..end)
insteadCreates 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 exceedend
.begin
andend
must be byte positions within the string slice.begin
andend
must lie on UTF-8 sequence boundaries.
§Examples
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));
}
1.4.0 · sourcepub fn split_at(&self, mid: usize) -> (&str, &str)
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. For a non-panicking
alternative see split_at_checked
.
§Examples
let s = "Per Martin-Löf";
let (first, last) = s.split_at(3);
assert_eq!("Per", first);
assert_eq!(" Martin-Löf", last);
1.80.0 · sourcepub fn split_at_checked(&self, mid: usize) -> Option<(&str, &str)>
pub fn split_at_checked(&self, mid: usize) -> Option<(&str, &str)>
Divide one string slice into two at an index.
The argument, mid
, should be a valid byte offset from the start of the
string. It must also be on the boundary of a UTF-8 code point. The
method returns None
if that’s not the case.
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_checked
method.
§Examples
let s = "Per Martin-Löf";
let (first, last) = s.split_at_checked(3).unwrap();
assert_eq!("Per", first);
assert_eq!(" Martin-Löf", last);
assert_eq!(None, s.split_at_checked(13)); // Inside “ö”
assert_eq!(None, s.split_at_checked(16)); // Beyond the string length
1.0.0 · sourcepub fn chars(&self) -> Chars<'_>
pub fn chars(&self) -> Chars<'_>
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 might not match your idea of what a ‘character’ is. Iteration
over grapheme clusters may be what you actually want. This functionality
is not provided by Rust’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, char
s might not match your 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());
1.0.0 · sourcepub fn char_indices(&self) -> CharIndices<'_>
pub fn char_indices(&self) -> CharIndices<'_>
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());
Remember, char
s might not match your 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 previous 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 · sourcepub fn bytes(&self) -> Bytes<'_>
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
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 · sourcepub fn split_whitespace(&self) -> SplitWhitespace<'_>
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.
‘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());
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 · sourcepub fn split_ascii_whitespace(&self) -> SplitAsciiWhitespace<'_>
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 · sourcepub fn lines(&self) -> Lines<'_>
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.
Note that any carriage return (\r
) not immediately followed by a
line feed (\n
) does not split a line. These carriage returns are
thereby included in the produced lines.
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\r";
let mut lines = text.lines();
assert_eq!(Some("foo"), lines.next());
assert_eq!(Some("bar"), lines.next());
assert_eq!(Some(""), lines.next());
// Trailing carriage return is included in the last line
assert_eq!(Some("baz\r"), lines.next());
assert_eq!(None, lines.next());
The final line does not require any ending:
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 · sourcepub fn lines_any(&self) -> LinesAny<'_>
👎Deprecated since 1.4.0: use lines() instead now
pub fn lines_any(&self) -> LinesAny<'_>
An iterator over the lines of a string.
1.8.0 · sourcepub fn encode_utf16(&self) -> EncodeUtf16<'_>
pub fn encode_utf16(&self) -> EncodeUtf16<'_>
Returns an iterator of u16
over the string encoded as UTF-16.
§Examples
let text = "Zażółć gęślą jaźń";
let utf8_len = text.len();
let utf16_len = text.encode_utf16().count();
assert!(utf16_len <= utf8_len);
1.0.0 · sourcepub fn contains<'a, P>(&'a self, pat: P) -> boolwhere
P: Pattern<'a>,
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 char
s, or a
function or closure that determines if a character matches.
§Examples
let bananas = "bananas";
assert!(bananas.contains("nana"));
assert!(!bananas.contains("apples"));
1.0.0 · sourcepub fn starts_with<'a, P>(&'a self, pat: P) -> boolwhere
P: Pattern<'a>,
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
, in which case this function will return true if
the &str
is a prefix of this string slice.
The pattern can also be a char
, a slice of char
s, or a
function or closure that determines if a character matches.
These will only be checked against the first character of this string slice.
Look at the second example below regarding behavior for slices of char
s.
§Examples
let bananas = "bananas";
assert!(bananas.starts_with("bana"));
assert!(!bananas.starts_with("nana"));
let bananas = "bananas";
// Note that both of these assert successfully.
assert!(bananas.starts_with(&['b', 'a', 'n', 'a']));
assert!(bananas.starts_with(&['a', 'b', 'c', 'd']));
1.0.0 · sourcepub fn ends_with<'a, P>(&'a self, pat: P) -> bool
pub fn ends_with<'a, P>(&'a self, pat: P) -> bool
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 char
s, or a
function or closure that determines if a character matches.
§Examples
let bananas = "bananas";
assert!(bananas.ends_with("anas"));
assert!(!bananas.ends_with("nana"));
1.0.0 · sourcepub fn find<'a, P>(&'a self, pat: P) -> Option<usize>where
P: Pattern<'a>,
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 doesn’t match.
The pattern can be a &str
, char
, a slice of char
s, or a
function or closure that determines if a character matches.
§Examples
Simple patterns:
let s = "Löwe 老虎 Léopard Gepardi";
assert_eq!(s.find('L'), Some(0));
assert_eq!(s.find('é'), Some(14));
assert_eq!(s.find("pard"), Some(17));
More complex patterns using point-free style and closures:
let s = "Löwe 老虎 Léopard";
assert_eq!(s.find(char::is_whitespace), Some(5));
assert_eq!(s.find(char::is_lowercase), Some(1));
assert_eq!(s.find(|c: char| c.is_whitespace() || c.is_lowercase()), Some(1));
assert_eq!(s.find(|c: char| (c < 'o') && (c > 'a')), Some(4));
Not finding the pattern:
let s = "Löwe 老虎 Léopard";
let x: &[_] = &['1', '2'];
assert_eq!(s.find(x), None);
1.0.0 · sourcepub fn rfind<'a, P>(&'a self, pat: P) -> Option<usize>
pub fn rfind<'a, P>(&'a self, pat: P) -> Option<usize>
Returns the byte index for the first character of the last match of the pattern in this string slice.
Returns None
if the pattern doesn’t match.
The pattern can be a &str
, char
, a slice of char
s, or a
function or closure that determines if a character matches.
§Examples
Simple patterns:
let s = "Löwe 老虎 Léopard Gepardi";
assert_eq!(s.rfind('L'), Some(13));
assert_eq!(s.rfind('é'), Some(14));
assert_eq!(s.rfind("pard"), Some(24));
More complex patterns with closures:
let s = "Löwe 老虎 Léopard";
assert_eq!(s.rfind(char::is_whitespace), Some(12));
assert_eq!(s.rfind(char::is_lowercase), Some(20));
Not finding the pattern:
let s = "Löwe 老虎 Léopard";
let x: &[_] = &['1', '2'];
assert_eq!(s.rfind(x), None);
1.0.0 · sourcepub fn split<'a, P>(&'a self, pat: P) -> Split<'a, P>where
P: Pattern<'a>,
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 char
s, 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:
assert_eq!(d, &["a", "b", "c"]);
Use split_whitespace
for this behavior.
1.51.0 · sourcepub fn split_inclusive<'a, P>(&'a self, pat: P) -> SplitInclusive<'a, P>where
P: Pattern<'a>,
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 char
s, 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 · sourcepub fn rsplit<'a, P>(&'a self, pat: P) -> RSplit<'a, P>
pub fn rsplit<'a, P>(&'a self, pat: P) -> RSplit<'a, P>
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 char
s, 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 · sourcepub fn split_terminator<'a, P>(&'a self, pat: P) -> SplitTerminator<'a, P>where
P: Pattern<'a>,
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 char
s, 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
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 · sourcepub fn rsplit_terminator<'a, P>(&'a self, pat: P) -> RSplitTerminator<'a, P>
pub fn rsplit_terminator<'a, P>(&'a self, pat: P) -> RSplitTerminator<'a, P>
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 char
s, 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 · sourcepub fn splitn<'a, P>(&'a self, n: usize, pat: P) -> SplitN<'a, P>where
P: Pattern<'a>,
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 n
th substring)
will contain the remainder of the string.
The pattern can be a &str
, char
, a slice of char
s, 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 · sourcepub fn rsplitn<'a, P>(&'a self, n: usize, pat: P) -> RSplitN<'a, P>
pub fn rsplitn<'a, P>(&'a self, n: usize, pat: P) -> RSplitN<'a, P>
An iterator over substrings of this string slice, separated by a
pattern, starting from the end of the string, restricted to returning
at most n
items.
If n
substrings are returned, the last substring (the n
th substring)
will contain the remainder of the string.
The pattern can be a &str
, char
, a slice of char
s, 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 · sourcepub fn split_once<'a, P>(&'a self, delimiter: P) -> Option<(&'a str, &'a str)>where
P: Pattern<'a>,
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 · sourcepub fn rsplit_once<'a, P>(&'a self, delimiter: P) -> Option<(&'a str, &'a str)>
pub fn rsplit_once<'a, P>(&'a self, delimiter: P) -> Option<(&'a str, &'a str)>
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 · sourcepub fn matches<'a, P>(&'a self, pat: P) -> Matches<'a, P>where
P: Pattern<'a>,
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 char
s, 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
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 · sourcepub fn rmatches<'a, P>(&'a self, pat: P) -> RMatches<'a, P>
pub fn rmatches<'a, P>(&'a self, pat: P) -> RMatches<'a, P>
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 char
s, 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
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 · sourcepub fn match_indices<'a, P>(&'a self, pat: P) -> MatchIndices<'a, P>where
P: Pattern<'a>,
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 char
s, 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
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 · sourcepub fn rmatch_indices<'a, P>(&'a self, pat: P) -> RMatchIndices<'a, P>
pub fn rmatch_indices<'a, P>(&'a self, pat: P) -> RMatchIndices<'a, P>
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 char
s, 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
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 · sourcepub fn trim(&self) -> &str
pub fn trim(&self) -> &str
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
, which includes newlines.
§Examples
let s = "\n Hello\tworld\t\n";
assert_eq!("Hello\tworld", s.trim());
1.30.0 · sourcepub fn trim_start(&self) -> &str
pub fn trim_start(&self) -> &str
Returns a string slice with leading whitespace removed.
‘Whitespace’ 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 = " עברית ";
assert!(Some('ע') == s.trim_start().chars().next());
1.30.0 · sourcepub fn trim_end(&self) -> &str
pub fn trim_end(&self) -> &str
Returns a string slice with trailing whitespace removed.
‘Whitespace’ 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 = " עברית ";
assert!(Some('ת') == s.trim_end().chars().rev().next());
1.0.0 · sourcepub fn trim_left(&self) -> &str
👎Deprecated since 1.33.0: superseded by trim_start
pub fn trim_left(&self) -> &str
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());
Directionality:
let s = " English";
assert!(Some('E') == s.trim_left().chars().next());
let s = " עברית";
assert!(Some('ע') == s.trim_left().chars().next());
1.0.0 · sourcepub fn trim_right(&self) -> &str
👎Deprecated since 1.33.0: superseded by trim_end
pub fn trim_right(&self) -> &str
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());
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());
1.0.0 · sourcepub fn trim_matches<'a, P>(&'a self, pat: P) -> &'a str
pub fn trim_matches<'a, P>(&'a self, pat: P) -> &'a str
Returns a string slice with all prefixes and suffixes that match a pattern repeatedly removed.
The pattern can be a char
, a slice of char
s, 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 · sourcepub fn trim_start_matches<'a, P>(&'a self, pat: P) -> &'a strwhere
P: Pattern<'a>,
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 char
s, 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
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 · sourcepub fn strip_prefix<'a, P>(&'a self, prefix: P) -> Option<&'a str>where
P: Pattern<'a>,
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 the 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 char
s, 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 · sourcepub fn strip_suffix<'a, P>(&'a self, suffix: P) -> Option<&'a str>
pub fn strip_suffix<'a, P>(&'a self, suffix: P) -> Option<&'a str>
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 char
s, 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 · sourcepub fn trim_end_matches<'a, P>(&'a self, pat: P) -> &'a str
pub fn trim_end_matches<'a, P>(&'a self, pat: P) -> &'a str
Returns a string slice with all suffixes that match a pattern repeatedly removed.
The pattern can be a &str
, char
, a slice of char
s, 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 · sourcepub fn trim_left_matches<'a, P>(&'a self, pat: P) -> &'a strwhere
P: Pattern<'a>,
👎Deprecated since 1.33.0: superseded by trim_start_matches
pub fn trim_left_matches<'a, P>(&'a self, pat: P) -> &'a strwhere
P: Pattern<'a>,
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 char
s, or a
function or 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
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 · sourcepub fn trim_right_matches<'a, P>(&'a self, pat: P) -> &'a str
👎Deprecated since 1.33.0: superseded by trim_end_matches
pub fn trim_right_matches<'a, P>(&'a self, pat: P) -> &'a str
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 char
s, or a
function or 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_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 · sourcepub fn parse<F>(&self) -> Result<F, <F as FromStr>::Err>where
F: FromStr,
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 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 into 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);
Using the ‘turbofish’ instead of annotating four
:
let four = "4".parse::<u32>();
assert_eq!(Ok(4), four);
Failing to parse:
let nope = "j".parse::<u32>();
assert!(nope.is_err());
1.23.0 · sourcepub fn is_ascii(&self) -> bool
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 = "Grüße, Jürgen ❤";
assert!(ascii.is_ascii());
assert!(!non_ascii.is_ascii());
sourcepub fn as_ascii(&self) -> Option<&[AsciiChar]>
🔬This is a nightly-only experimental API. (ascii_char
)
pub fn as_ascii(&self) -> Option<&[AsciiChar]>
ascii_char
)If this string slice is_ascii
, returns it as a slice
of ASCII characters, otherwise returns None
.
1.23.0 · sourcepub fn eq_ignore_ascii_case(&self, other: &str) -> bool
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!("Ferrös".eq_ignore_ascii_case("FERRöS"));
assert!(!"Ferrös".eq_ignore_ascii_case("FERRÖS"));
1.80.0 · sourcepub fn trim_ascii_start(&self) -> &str
pub fn trim_ascii_start(&self) -> &str
Returns a string slice with leading ASCII whitespace removed.
‘Whitespace’ refers to the definition used by
u8::is_ascii_whitespace
.
§Examples
assert_eq!(" \t \u{3000}hello world\n".trim_ascii_start(), "\u{3000}hello world\n");
assert_eq!(" ".trim_ascii_start(), "");
assert_eq!("".trim_ascii_start(), "");
1.80.0 · sourcepub fn trim_ascii_end(&self) -> &str
pub fn trim_ascii_end(&self) -> &str
Returns a string slice with trailing ASCII whitespace removed.
‘Whitespace’ refers to the definition used by
u8::is_ascii_whitespace
.
§Examples
assert_eq!("\r hello world\u{3000}\n ".trim_ascii_end(), "\r hello world\u{3000}");
assert_eq!(" ".trim_ascii_end(), "");
assert_eq!("".trim_ascii_end(), "");
1.80.0 · sourcepub fn trim_ascii(&self) -> &str
pub fn trim_ascii(&self) -> &str
Returns a string slice with leading and trailing ASCII whitespace removed.
‘Whitespace’ refers to the definition used by
u8::is_ascii_whitespace
.
§Examples
assert_eq!("\r hello world\n ".trim_ascii(), "hello world");
assert_eq!(" ".trim_ascii(), "");
assert_eq!("".trim_ascii(), "");
1.34.0 · sourcepub fn escape_debug(&self) -> EscapeDebug<'_>
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 "❤\n!".escape_debug() {
print!("{c}");
}
println!();
Using println!
directly:
println!("{}", "❤\n!".escape_debug());
Both are equivalent to:
println!("❤\\n!");
Using to_string
:
assert_eq!("❤\n!".escape_debug().to_string(), "❤\\n!");
1.34.0 · sourcepub fn escape_default(&self) -> EscapeDefault<'_>
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 "❤\n!".escape_default() {
print!("{c}");
}
println!();
Using println!
directly:
println!("{}", "❤\n!".escape_default());
Both are equivalent to:
println!("\\u{{2764}}\\n!");
Using to_string
:
assert_eq!("❤\n!".escape_default().to_string(), "\\u{2764}\\n!");
1.34.0 · sourcepub fn escape_unicode(&self) -> EscapeUnicode<'_>
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 "❤\n!".escape_unicode() {
print!("{c}");
}
println!();
Using println!
directly:
println!("{}", "❤\n!".escape_unicode());
Both are equivalent to:
println!("\\u{{2764}}\\u{{a}}\\u{{21}}");
Using to_string
:
assert_eq!("❤\n!".escape_unicode().to_string(), "\\u{2764}\\u{a}\\u{21}");
1.0.0 · sourcepub fn replace<'a, P>(&'a self, from: P, to: &str) -> Stringwhere
P: Pattern<'a>,
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 doesn’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 · sourcepub fn replacen<'a, P>(&'a self, pat: P, to: &str, count: usize) -> Stringwhere
P: Pattern<'a>,
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 doesn’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 · sourcepub fn to_lowercase(&self) -> String
pub fn to_lowercase(&self) -> String
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());
A tricky example, with sigma:
let sigma = "Σ";
assert_eq!("σ", sigma.to_lowercase());
// but at the end of a word, it's ς, not σ:
let odysseus = "ὈΔΥΣΣΕΎΣ";
assert_eq!("ὀδυσσεύς", odysseus.to_lowercase());
Languages without case are not changed:
let new_year = "农历新年";
assert_eq!(new_year, new_year.to_lowercase());
1.2.0 · sourcepub fn to_uppercase(&self) -> String
pub fn to_uppercase(&self) -> String
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());
Scripts without case are not changed:
let new_year = "农历新年";
assert_eq!(new_year, new_year.to_uppercase());
One character can become multiple:
let s = "tschüß";
assert_eq!("TSCHÜSS", s.to_uppercase());
1.16.0 · sourcepub fn repeat(&self, n: usize) -> String
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:
// this will panic at runtime
let huge = "0123456789abcdef".repeat(usize::MAX);
1.23.0 · sourcepub fn to_ascii_uppercase(&self) -> String
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 ‘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());
1.23.0 · sourcepub fn to_ascii_lowercase(&self) -> String
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 ‘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());
Trait Implementations§
source§impl AsRef<str> for BaseNString
impl AsRef<str> for BaseNString
source§impl Deref for BaseNString
impl Deref for BaseNString
Auto Trait Implementations§
impl Freeze for BaseNString
impl RefUnwindSafe for BaseNString
impl Send for BaseNString
impl Sync for BaseNString
impl Unpin for BaseNString
impl UnwindSafe for BaseNString
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§impl<T> WithSubscriber for T
impl<T> WithSubscriber for T
source§fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
source§fn with_current_subscriber(self) -> WithDispatch<Self>
fn with_current_subscriber(self) -> WithDispatch<Self>
impl<'a, T> Captures<'a> for Twhere
T: ?Sized,
Layout§
Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...)
attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.
Size: 136 bytes