pub trait Pattern<'a>: Sized {
type Searcher: Searcher<'a>;
// Required method
fn into_searcher(self, haystack: &'a str) -> Self::Searcher;
// Provided methods
fn is_contained_in(self, haystack: &'a str) -> bool { ... }
fn is_prefix_of(self, haystack: &'a str) -> bool { ... }
fn is_suffix_of(self, haystack: &'a str) -> bool
where Self::Searcher: ReverseSearcher<'a> { ... }
fn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str> { ... }
fn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str>
where Self::Searcher: ReverseSearcher<'a> { ... }
}
pattern
#27721)Expand description
A string pattern.
A Pattern<'a>
expresses that the implementing type
can be used as a string pattern for searching in a &'a str
.
For example, both 'a'
and "aa"
are patterns that
would match at index 1
in the string "baaaab"
.
The trait itself acts as a builder for an associated
Searcher
type, which does the actual work of finding
occurrences of the pattern in a string.
Depending on the type of the pattern, the behaviour of methods like
str::find
and str::contains
can change. The table below describes
some of those behaviours.
Pattern type | Match condition |
---|---|
&str | is substring |
char | is contained in string |
&[char] | any char in slice is contained in string |
F: FnMut(char) -> bool | F returns true for a char in string |
&&str | is substring |
&String | is substring |
§Examples
// &str
assert_eq!("abaaa".find("ba"), Some(1));
assert_eq!("abaaa".find("bac"), None);
// char
assert_eq!("abaaa".find('a'), Some(0));
assert_eq!("abaaa".find('b'), Some(1));
assert_eq!("abaaa".find('c'), None);
// &[char; N]
assert_eq!("ab".find(&['b', 'a']), Some(0));
assert_eq!("abaaa".find(&['a', 'z']), Some(0));
assert_eq!("abaaa".find(&['c', 'd']), None);
// &[char]
assert_eq!("ab".find(&['b', 'a'][..]), Some(0));
assert_eq!("abaaa".find(&['a', 'z'][..]), Some(0));
assert_eq!("abaaa".find(&['c', 'd'][..]), None);
// FnMut(char) -> bool
assert_eq!("abcdef_z".find(|ch| ch > 'd' && ch < 'y'), Some(4));
assert_eq!("abcddd_z".find(|ch| ch > 'd' && ch < 'y'), None);
RunRequired Associated Types§
Required Methods§
sourcefn into_searcher(self, haystack: &'a str) -> Self::Searcher
fn into_searcher(self, haystack: &'a str) -> Self::Searcher
pattern
#27721)Constructs the associated searcher from
self
and the haystack
to search in.
Provided Methods§
sourcefn is_contained_in(self, haystack: &'a str) -> bool
fn is_contained_in(self, haystack: &'a str) -> bool
pattern
#27721)Checks whether the pattern matches anywhere in the haystack
sourcefn is_prefix_of(self, haystack: &'a str) -> bool
fn is_prefix_of(self, haystack: &'a str) -> bool
pattern
#27721)Checks whether the pattern matches at the front of the haystack
sourcefn is_suffix_of(self, haystack: &'a str) -> boolwhere
Self::Searcher: ReverseSearcher<'a>,
fn is_suffix_of(self, haystack: &'a str) -> boolwhere
Self::Searcher: ReverseSearcher<'a>,
pattern
#27721)Checks whether the pattern matches at the back of the haystack
sourcefn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str>
fn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str>
pattern
#27721)Removes the pattern from the front of haystack, if it matches.
sourcefn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str>where
Self::Searcher: ReverseSearcher<'a>,
fn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str>where
Self::Searcher: ReverseSearcher<'a>,
pattern
#27721)Removes the pattern from the back of haystack, if it matches.
Object Safety§
Implementors§
source§impl<'a> Pattern<'a> for char
impl<'a> Pattern<'a> for char
Searches for chars that are equal to a given char
.
§Examples
assert_eq!("Hello world".find('o'), Some(4));
Runtype Searcher = CharSearcher<'a>
source§impl<'a, 'b> Pattern<'a> for &'b str
impl<'a, 'b> Pattern<'a> for &'b str
Non-allocating substring search.
Will handle the pattern ""
as returning empty matches at each character
boundary.
§Examples
assert_eq!("Hello world".find("world"), Some(6));
Runtype Searcher = StrSearcher<'a, 'b>
source§impl<'a, 'b> Pattern<'a> for &'b String
impl<'a, 'b> Pattern<'a> for &'b String
source§impl<'a, 'b> Pattern<'a> for &'b [char]
impl<'a, 'b> Pattern<'a> for &'b [char]
Searches for chars that are equal to any of the char
s in the slice.
§Examples
assert_eq!("Hello world".find(&['l', 'l'] as &[_]), Some(2));
assert_eq!("Hello world".find(&['l', 'l'][..]), Some(2));
Runtype Searcher = CharSliceSearcher<'a, 'b>
source§impl<'a, 'b, 'c> Pattern<'a> for &'c &'b str
impl<'a, 'b, 'c> Pattern<'a> for &'c &'b str
Delegates to the &str
impl.
type Searcher = StrSearcher<'a, 'b>
source§impl<'a, 'b, const N: usize> Pattern<'a> for &'b [char; N]
impl<'a, 'b, const N: usize> Pattern<'a> for &'b [char; N]
Searches for chars that are equal to any of the char
s in the array.
§Examples
assert_eq!("Hello world".find(&['o', 'l']), Some(2));
assert_eq!("Hello world".find(&['h', 'w']), Some(6));
Run