Trait alloc::str::pattern::Pattern

source · 
pub trait Pattern<'a>: Sized {
    type Searcher: Searcher<'a>;

    fn into_searcher(self, haystack: &'a str) -> Self::Searcher;

    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>,
    { ... }
}
🔬This is a nightly-only experimental API. (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 typeMatch condition
&stris substring
charis contained in string
&[char]any char in slice is contained in string
F: FnMut(char) -> boolF returns true for a char in string
&&stris substring
&Stringis 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);
Run

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.

Implementors

Searches for chars that are equal to a given char.

Examples

assert_eq!("Hello world".find('o'), Some(4));
Run

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));
Run

A convenience impl that delegates to the impl for &str.

Examples

assert_eq!(String::from("Hello world").find("world"), Some(6));
Run

Searches for chars that are equal to any of the chars in the slice.

Examples

assert_eq!("Hello world".find(&['l', 'l'] as &[_]), Some(2));
assert_eq!("Hello world".find(&['l', 'l'][..]), Some(2));
Run

Delegates to the &str impl.

Searches for chars that are equal to any of the chars in the array.

Examples

assert_eq!("Hello world".find(&['l', 'l']), Some(2));
assert_eq!("Hello world".find(&['l', 'l']), Some(2));
Run

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));
Run

Searches for chars that are equal to any of the chars in the array.

Examples

assert_eq!("Hello world".find(['l', 'l']), Some(2));
assert_eq!("Hello world".find(['l', 'l']), Some(2));
Run