GeezerVison is showing doc.rust-lang.org — Pattern in std::str::pattern - Rust pub trait Pattern: Sized {
type Searcher<'a>: Searcher<'a>;
// Required method
fn into_searcher(self, haystack: &str) -> Self::Searcher<'_>;
// Provided methods
fn is_contained_in(self, haystack: &str) -> bool { ... }
fn is_prefix_of(self, haystack: &str) -> bool { ... }
fn is_suffix_of<'a>(self, haystack: &'a str) -> bool
where Self::Searcher<'a>: ReverseSearcher<'a> { ... }
fn strip_prefix_of(self, haystack: &str) -> Option<&str> { ... }
fn strip_suffix_of<'a>(self, haystack: &'a str) -> Option<&'a str>
where Self::Searcher<'a>: ReverseSearcher<'a> { ... }
fn as_utf8_pattern(&self) -> Option<Utf8Pattern<'_>> { ... }
}
🔬This is a nightly-only experimental API. (pattern #27721) Expand descriptionA string pattern.
A Pattern expresses that the implementing type
can be used as a string pattern for searching in 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 behavior of methods like
str::find and str::contains can change. The table below describes
some of those behaviors.
| 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);
Required Associated Types§🔬This is a nightly-only experimental API. (pattern #27721)
Associated searcher for this pattern
Required Methods§🔬This is a nightly-only experimental API. (pattern #27721)
Constructs the associated searcher from
self and the haystack to search in.
Provided Methods§🔬This is a nightly-only experimental API. (pattern #27721)
Checks whether the pattern matches anywhere in the haystack
🔬This is a nightly-only experimental API. (pattern #27721)
Checks whether the pattern matches at the front of the haystack
🔬This is a nightly-only experimental API. (pattern #27721)
Checks whether the pattern matches at the back of the haystack
🔬This is a nightly-only experimental API. (pattern #27721)
Removes the pattern from the front of haystack, if it matches.
🔬This is a nightly-only experimental API. (pattern #27721)
Removes the pattern from the back of haystack, if it matches.
🔬This is a nightly-only experimental API. (pattern #27721)
Returns the pattern as UTF-8 if possible.
Dyn Compatibility§This trait is not dyn compatible. In older versions of Rust, dyn compatibility was called "object safety". Implementors§Source§Searches for chars that are equal to a given char.
§Examples
assert_eq!("Hello world".find('o'), Some(4));
Source§Searches for chars that are equal to any of the chars in the array.
§Examples
assert_eq!("Hello world".find(&['o', 'l']), Some(2));
assert_eq!("Hello world".find(&['h', 'w']), Some(6));
Source§A convenience impl that delegates to the impl for &str.
§Examples
assert_eq!(String::from("Hello world").find("world"), Some(6));
Source§Searches for chars that are equal to any of the chars in the slice.
§Examples
assert_eq!("Hello world".find(&['o', 'l'][..]), Some(2));
assert_eq!("Hello world".find(&['h', 'w'][..]), Some(6));
Source§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));
Source§Searches for chars that match the given predicate.
§Examples
assert_eq!("Hello world".find(char::is_uppercase), Some(0));
assert_eq!("Hello world".find(|c| "aeiou".contains(c)), Some(1));
Source§Searches for chars that are equal to any of the chars in the array.
§Examples
assert_eq!("Hello world".find(['o', 'l']), Some(2));
assert_eq!("Hello world".find(['h', 'w']), Some(6));
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