Enum mime::SubLevel
[−]
[src]
pub enum SubLevel { Star, Plain, Html, Xml, Javascript, Css, Json, WwwFormUrlEncoded, Msgpack, FormData, Png, Gif, Bmp, Jpeg, Ext(String), }
Variants
Star | ||
Plain | ||
Html | ||
Xml | ||
Javascript | ||
Css | ||
Json | ||
WwwFormUrlEncoded | ||
Msgpack | ||
FormData | ||
Png | ||
Gif | ||
Bmp | ||
Jpeg | ||
Ext |
Methods
impl SubLevel
Methods from Deref<Target=str>
1.0.0fn len(&self) -> usize
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);
1.0.0fn is_empty(&self) -> bool
Returns true if this slice has a length of zero bytes.
Examples
Basic usage:
let s = ""; assert!(s.is_empty()); let s = "not empty"; assert!(!s.is_empty());
fn is_char_boundary(&self, index: usize) -> bool
str_char
): it is unclear whether this method pulls its weight with the existence of the char_indices iterator or this method may want to be replaced with checked slicing
Checks that index
-th byte lies at the start and/or end of a
UTF-8 code point sequence.
The start and end of the string (when index == self.len()
) are
considered to be
boundaries.
Returns false
if index
is greater than self.len()
.
Examples
#![feature(str_char)] let s = "Löwe 老虎 Léopard"; assert!(s.is_char_boundary(0)); // start of `老` assert!(s.is_char_boundary(6)); assert!(s.is_char_boundary(s.len())); // second byte of `ö` assert!(!s.is_char_boundary(2)); // third byte of `老` assert!(!s.is_char_boundary(8));
1.0.0fn as_bytes(&self) -> &[u8]
Converts a string slice to a byte slice.
Examples
Basic usage:
let bytes = "bors".as_bytes(); assert_eq!(b"bors", bytes);
1.0.0fn 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.
Examples
Basic usage:
let s = "Hello"; let ptr = s.as_ptr();
1.0.0unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str
Creates a string slice from another string slice, bypassing safety checks.
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)); }
1.5.0unsafe fn slice_mut_unchecked(&mut self, begin: usize, end: usize) -> &mut str
Creates a string slice from another string slice, bypassing safety checks.
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.
fn char_range_at(&self, start: usize) -> CharRange
str_char
): often replaced by char_indices, this method may be removed in favor of just char_at() or eventually removed altogether
Given a byte position, returns the next char
and its index.
Panics
If i
is greater than or equal to the length of the string.
If i
is not the index of the beginning of a valid UTF-8 sequence.
Examples
This example manually iterates through the code points of a string;
this should normally be
done by .chars()
or .char_indices()
.
#![feature(str_char)] use std::str::CharRange; let s = "中华Việt Nam"; let mut i = 0; while i < s.len() { let CharRange {ch, next} = s.char_range_at(i); println!("{}: {}", i, ch); i = next; }
This outputs:
0: 中
3: 华
6: V
7: i
8: e
9:
11:
13: t
14:
15: N
16: a
17: m
fn char_range_at_reverse(&self, start: usize) -> CharRange
str_char
): often replaced by char_indices, this method may be removed in favor of just char_at_reverse() or eventually removed altogether
Given a byte position, returns the previous char
and its position.
Note that Unicode has many features, such as combining marks, ligatures, and direction marks, that need to be taken into account to correctly reverse a string.
Returns 0 for next index if called on start index 0.
Panics
If i
is greater than the length of the string.
If i
is not an index following a valid UTF-8 sequence.
Examples
This example manually iterates through the code points of a string;
this should normally be
done by .chars().rev()
or .char_indices()
.
#![feature(str_char)] use std::str::CharRange; let s = "中华Việt Nam"; let mut i = s.len(); while i > 0 { let CharRange {ch, next} = s.char_range_at_reverse(i); println!("{}: {}", i, ch); i = next; }
This outputs:
18: m
17: a
16: N
15:
14: t
13:
11:
9: e
8: i
7: V
6: 华
3: 中
fn char_at(&self, i: usize) -> char
str_char
): frequently replaced by the chars() iterator, this method may be removed or possibly renamed in the future; it is normally replaced by chars/char_indices iterators or by getting the first char from a subslice
Given a byte position, returns the char
at that position.
Panics
If i
is greater than or equal to the length of the string.
If i
is not the index of the beginning of a valid UTF-8 sequence.
Examples
#![feature(str_char)] let s = "abπc"; assert_eq!(s.char_at(1), 'b'); assert_eq!(s.char_at(2), 'π'); assert_eq!(s.char_at(4), 'c');
fn char_at_reverse(&self, i: usize) -> char
str_char
): see char_at for more details, but reverse semantics are also somewhat unclear, especially with which cases generate panics
Given a byte position, returns the char
at that position, counting
from the end.
Panics
If i
is greater than the length of the string.
If i
is not an index following a valid UTF-8 sequence.
Examples
#![feature(str_char)] let s = "abπc"; assert_eq!(s.char_at_reverse(1), 'a'); assert_eq!(s.char_at_reverse(2), 'b'); assert_eq!(s.char_at_reverse(3), 'π');
fn slice_shift_char(&self) -> Option<(char, &str)>
str_char
): awaiting conventions about shifting and slices and may not be warranted with the existence of the chars and/or char_indices iterators
Retrieves the first char
from a &str
and returns it.
Note that a single Unicode character (grapheme cluster)
can be composed of multiple char
s.
This does not allocate a new string; instead, it returns a slice that points one code point beyond the code point that was shifted.
None
is returned if the slice is empty.
Examples
#![feature(str_char)] let s = "Łódź"; // \u{141}o\u{301}dz\u{301} let (c, s1) = s.slice_shift_char().unwrap(); assert_eq!(c, 'Ł'); assert_eq!(s1, "ódź"); let (c, s2) = s1.slice_shift_char().unwrap(); assert_eq!(c, 'o'); assert_eq!(s2, "\u{301}dz\u{301}");
1.4.0fn 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
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);
1.4.0fn split_at_mut(&mut self, mid: usize) -> (&mut str, &mut str)
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 s = "Per Martin-Löf"; let (first, last) = s.split_at(3); assert_eq!("Per", first); assert_eq!(" Martin-Löf", last);
1.0.0fn 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 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());
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());
1.0.0fn 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 may not match your human intuition about characters:
let y = "y̆"; let mut char_indices = y.char_indices(); assert_eq!(Some((0, 'y')), char_indices.next()); // not (0, 'y̆') assert_eq!(Some((1, '\u{0306}')), char_indices.next()); assert_eq!(None, char_indices.next());
1.0.0fn bytes(&self) -> Bytes
An iterator over the bytes of a string slice.
As a string slice consists of a sequence of bytes, we can iterate through a string slice by byte. This method returns such an iterator.
Examples
Basic usage:
let mut bytes = "bors".bytes(); assert_eq!(Some(b'b'), bytes.next()); assert_eq!(Some(b'o'), bytes.next()); assert_eq!(Some(b'r'), bytes.next()); assert_eq!(Some(b's'), bytes.next()); assert_eq!(None, bytes.next());
1.1.0fn split_whitespace(&self) -> SplitWhitespace
Split a string slice by whitespace.
The iterator returned will return string slices that are sub-slices of the original string slice, separated by any amount of whitespace.
'Whitespace' is defined according to the terms of the Unicode Derived
Core Property White_Space
.
Examples
Basic usage:
let mut iter = "A few words".split_whitespace(); assert_eq!(Some("A"), iter.next()); assert_eq!(Some("few"), iter.next()); assert_eq!(Some("words"), iter.next()); assert_eq!(None, iter.next());
All kinds of whitespace are considered:
let mut iter = " Mary had\ta\u{2009}little \n\t lamb".split_whitespace(); assert_eq!(Some("Mary"), iter.next()); assert_eq!(Some("had"), iter.next()); assert_eq!(Some("a"), iter.next()); assert_eq!(Some("little"), iter.next()); assert_eq!(Some("lamb"), iter.next()); assert_eq!(None, iter.next());
1.0.0fn lines(&self) -> Lines
An iterator over the lines of a string, as string slices.
Lines are ended with either a newline (\n
) or a carriage return with
a line feed (\r\n
).
The final line ending is optional.
Examples
Basic usage:
let text = "foo\r\nbar\n\nbaz\n"; let mut lines = text.lines(); assert_eq!(Some("foo"), lines.next()); assert_eq!(Some("bar"), lines.next()); assert_eq!(Some(""), lines.next()); assert_eq!(Some("baz"), lines.next()); assert_eq!(None, lines.next());
The final line ending isn't required:
let text = "foo\nbar\n\r\nbaz"; let mut lines = text.lines(); assert_eq!(Some("foo"), lines.next()); assert_eq!(Some("bar"), lines.next()); assert_eq!(Some(""), lines.next()); assert_eq!(Some("baz"), lines.next()); assert_eq!(None, lines.next());
1.0.0fn lines_any(&self) -> LinesAny
: use lines() instead now
An iterator over the lines of a string.
fn utf16_units(&self) -> EncodeUtf16
: renamed to encode_utf16
Returns an iterator of u16
over the string encoded as UTF-16.
1.8.0fn encode_utf16(&self) -> EncodeUtf16
Returns an iterator of u16
over the string encoded as UTF-16.
1.0.0fn contains<'a, P>(&'a self, pat: P) -> bool where 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"));
1.0.0fn starts_with<'a, P>(&'a self, pat: P) -> bool where 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"));
1.0.0fn ends_with<'a, P>(&'a self, pat: P) -> bool where P: Pattern<'a>, P::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"));
1.0.0fn 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
, or a closure that determines if
a character matches.
Examples
Simple patterns:
let s = "Löwe 老虎 Léopard"; assert_eq!(s.find('L'), Some(0)); assert_eq!(s.find('é'), Some(14)); assert_eq!(s.find("Léopard"), Some(13));
More complex patterns with closures:
let s = "Löwe 老虎 Léopard"; assert_eq!(s.find(char::is_whitespace), Some(5)); assert_eq!(s.find(char::is_lowercase), Some(1));
Not finding the pattern:
let s = "Löwe 老虎 Léopard"; let x: &[_] = &['1', '2']; assert_eq!(s.find(x), None);
1.0.0fn rfind<'a, P>(&'a self, pat: P) -> Option<usize> where P: Pattern<'a>, P::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));
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);
1.0.0fn 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
, or a closure that determines the
split.
Iterator behavior
The returned iterator will be a DoubleEndedIterator
if the pattern
allows a reverse search and forward/reverse search yields the same
elements. This is true for, eg, char
but not for &str
.
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"]);
A more complex pattern, using a closure:
let v: Vec<&str> = "abc1defXghi".split(|c| c == '1' || c == 'X').collect(); assert_eq!(v, ["abc", "def", "ghi"]);
If a string contains multiple contiguous separators, you will end up with empty strings in the output:
let x = "||||a||b|c".to_string(); let d: Vec<_> = x.split('|').collect(); assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]);
This can lead to possibly surprising behavior when whitespace is used as the separator. This code is correct:
let x = " a b c".to_string(); let d: Vec<_> = x.split(' ').collect(); assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]);
It does not give you:
assert_eq!(d, &["a", "b", "c"]);
Use split_whitespace()
for this behavior.
1.0.0fn rsplit<'a, P>(&'a self, pat: P) -> RSplit<'a, P> where P: Pattern<'a>, P::Searcher: ReverseSearcher<'a>
An iterator over substrings of the given string slice, separated by characters matched by a pattern and yielded in reverse order.
The pattern can be a &str
, char
, or a closure 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"]);
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"]);
1.0.0fn 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
, or a closure 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, eg, 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", ""]);
1.0.0fn rsplit_terminator<'a, P>(&'a self, pat: P) -> RSplitTerminator<'a, P> where P: Pattern<'a>, P::Searcher: ReverseSearcher<'a>
An iterator over substrings of self
, separated by characters
matched by a pattern and yielded in reverse order.
The pattern can be a simple &str
, char
, or a closure that
determines the split.
Additional libraries might provide more complex patterns like
regular expressions.
Equivalent to split()
, except that the trailing substring is
skipped if empty.
This method can be used for string data that is terminated, rather than separated by a pattern.
Iterator behavior
The returned iterator requires that the pattern supports a reverse search, and it will be double ended if a forward/reverse search yields the same elements.
For iterating from the front, 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"]);
1.0.0fn splitn<'a, P>(&'a self, count: 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 count
items.
The last element returned, if any, will contain the remainder of the string slice.
The pattern can be a &str
, char
, or a closure 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, [""]);
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"]);
1.0.0fn rsplitn<'a, P>(&'a self, count: usize, pat: P) -> RSplitN<'a, P> where P: Pattern<'a>, P::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 count
items.
The last element returned, if any, will contain the remainder of the string slice.
The pattern can be a &str
, char
, or a closure 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"]);
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"]);
1.2.0fn matches<'a, P>(&'a self, pat: P) -> Matches<'a, P> where P: Pattern<'a>
An iterator over the matches of a pattern within the given string slice.
The pattern can be a &str
, char
, or a closure that
determines if a character matches.
Iterator behavior
The returned iterator will be a DoubleEndedIterator
if the pattern
allows a reverse search and forward/reverse search yields the same
elements. This is true for, eg, char
but not for &str
.
If the pattern allows a reverse search but its results might differ
from a forward search, the rmatches()
method can be used.
Examples
Basic usage:
let v: Vec<&str> = "abcXXXabcYYYabc".matches("abc").collect(); assert_eq!(v, ["abc", "abc", "abc"]); let v: Vec<&str> = "1abc2abc3".matches(char::is_numeric).collect(); assert_eq!(v, ["1", "2", "3"]);
1.2.0fn rmatches<'a, P>(&'a self, pat: P) -> RMatches<'a, P> where P: Pattern<'a>, P::Searcher: ReverseSearcher<'a>
An iterator over the 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"]);
1.5.0fn 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
, 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, eg, char
but not for &str
.
If the pattern allows a reverse search but its results might differ
from a forward search, the rmatch_indices()
method can be used.
Examples
Basic usage:
let v: Vec<_> = "abcXXXabcYYYabc".match_indices("abc").collect(); assert_eq!(v, [(0, "abc"), (6, "abc"), (12, "abc")]); let v: Vec<_> = "1abcabc2".match_indices("abc").collect(); assert_eq!(v, [(1, "abc"), (4, "abc")]); let v: Vec<_> = "ababa".match_indices("aba").collect(); assert_eq!(v, [(0, "aba")]); // only the first `aba`
1.5.0fn rmatch_indices<'a, P>(&'a self, pat: P) -> RMatchIndices<'a, P> where P: Pattern<'a>, P::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`
1.0.0fn 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
.
Examples
Basic usage:
let s = " Hello\tworld\t"; assert_eq!("Hello\tworld", s.trim());
1.0.0fn trim_left(&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
.
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());
1.0.0fn trim_right(&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
.
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());
1.0.0fn trim_matches<'a, P>(&'a self, pat: P) -> &'a str where P: Pattern<'a>, P::Searcher: DoubleEndedSearcher<'a>
Returns a string slice with all prefixes and suffixes that match a pattern repeatedly removed.
The pattern can be a &str
, char
, or a closure that determines
if a character matches.
Examples
Simple patterns:
assert_eq!("11foo1bar11".trim_matches('1'), "foo1bar"); assert_eq!("123foo1bar123".trim_matches(char::is_numeric), "foo1bar"); let x: &[_] = &['1', '2']; assert_eq!("12foo1bar12".trim_matches(x), "foo1bar");
A more complex pattern, using a closure:
assert_eq!("1foo1barXX".trim_matches(|c| c == '1' || c == 'X'), "foo1bar");
1.0.0fn trim_left_matches<'a, P>(&'a self, pat: P) -> &'a str where 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_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");
1.0.0fn trim_right_matches<'a, P>(&'a self, pat: P) -> &'a str where P: Pattern<'a>, P::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_right_matches('1'), "11foo1bar"); assert_eq!("123foo1bar123".trim_right_matches(char::is_numeric), "123foo1bar"); let x: &[_] = &['1', '2']; assert_eq!("12foo1bar12".trim_right_matches(x), "12foo1bar");
A more complex pattern, using a closure:
assert_eq!("1fooX".trim_left_matches(|c| c == '1' || c == 'X'), "fooX");
1.0.0fn parse<F>(&self) -> Result<F, F::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 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.
Example
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());
1.0.0fn replace<'a, P>(&'a self, from: P, to: &str) -> String where 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"));
When the pattern doesn't match:
let s = "this is old"; assert_eq!(s, s.replace("cookie monster", "little lamb"));
1.2.0fn 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
.
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());
1.2.0fn 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
.
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());
fn escape_default(&self) -> String
str_escape
): return type may change to be an iterator
Escapes each char in s
with char::escape_default
.
fn escape_unicode(&self) -> String
str_escape
): return type may change to be an iterator
Escapes each char in s
with char::escape_unicode
.