Structure_StringProcessing5.9.0
Regex
A regular expression.
- iOS
- 16.0+
- macOS
- 13.0+
- tvOS
- 16.0+
- watchOS
- 9.0+
struct Regex<Output>Regular expressions are a concise way of describing a pattern, which can help you match or extract portions of a string. You can create a Regex instance using regular expression syntax, either in a regex literal or a string.
// 'keyAndValue' is created using a regex literal
let keyAndValue = /(.+?): (.+)/
// 'simpleDigits' is created from a pattern in a string
let simpleDigits = try Regex("[0-9]+")You can use a Regex to search for a pattern in a string or substring. Call contains(_:) to check for the presence of a pattern, or firstMatch(of:) or matches(of:) to find matches.
let setting = "color: 161 103 230"
if setting.contains(simpleDigits) {
print("'\(setting)' contains some digits.")
}
// Prints "'color: 161 103 230' contains some digits."When you find a match, the resulting Match type includes an Match.output property that contains the matched substring along with any captures:
if let match = setting.firstMatch(of: keyAndValue) {
print("Key: \(match.1)")
print("Value: \(match.2)")
}
// Key: color
// Value: 161 103 230When you import the RegexBuilder module, you can also create Regex instances using a clear and flexible declarative syntax. Using this style, you can combine, capture, and transform regexes, RegexBuilder types, and custom parsers.
Citizens in _StringProcessing
Conformances
protocol RegexComponentA type that represents a regular expression.
Members
init(String, as: Output.Type) throws Creates a regular expression from the given string, using the specified capture type.
init?(Regex<AnyRegexOutput>, as: Output.Type) Creates a regular expression with a strongly-typed capture list from the given regular expression.
init(verbatim: String) Creates a regular expression that matches the given string exactly, as though every metacharacter in it was escaped.
var regex: Regex<Output>func anchorsMatchLineEndings(Bool) -> Regex<Regex<Output>.RegexOutput> Returns a regular expression where the start and end of input anchors (
^and$) also match against the start and end of a line.func asciiOnlyCharacterClasses(Bool) -> Regex<Regex<Output>.RegexOutput> Returns a regular expression that matches only ASCII characters when matching character classes.
func asciiOnlyDigits(Bool) -> Regex<Regex<Output>.RegexOutput> Returns a regular expression that matches only ASCII characters as digits.
func asciiOnlyWhitespace(Bool) -> Regex<Regex<Output>.RegexOutput> Returns a regular expression that matches only ASCII characters as space characters.
func asciiOnlyWordCharacters(Bool) -> Regex<Regex<Output>.RegexOutput> Returns a regular expression that matches only ASCII characters as word characters.
func contains(captureNamed: String) -> Bool Returns a Boolean value indicating whether a named capture with the given name exists.
func dotMatchesNewlines(Bool) -> Regex<Regex<Output>.RegexOutput> Returns a regular expression where the “any” metacharacter (
.) also matches against the start and end of a line.func firstMatch(in: String) throws -> Regex<Output>.Match? Returns the first match for this regex found in the given string.
func firstMatch(in: Substring) throws -> Regex<Output>.Match? Returns the first match for this regex found in the given substring.
func ignoresCase(Bool) -> Regex<Regex<Output>.RegexOutput> Returns a regular expression that ignores case when matching.
func matchingSemantics(RegexSemanticLevel) -> Regex<Regex<Output>.RegexOutput> Returns a regular expression that matches with the specified semantic level.
func prefixMatch(in: String) throws -> Regex<Output>.Match? Returns a match if this regex matches the given string at its start.
func prefixMatch(in: Substring) throws -> Regex<Output>.Match? Returns a match if this regex matches the given substring at its start.
func repetitionBehavior(RegexRepetitionBehavior) -> Regex<Regex<Output>.RegexOutput> Returns a regular expression where quantifiers use the specified behavior by default.
func wholeMatch(in: String) throws -> Regex<Output>.Match? Returns a match if this regex matches the given string in its entirety.
func wholeMatch(in: Substring) throws -> Regex<Output>.Match? Returns a match if this regex matches the given substring in its entirety.
func wordBoundaryKind(RegexWordBoundaryKind) -> Regex<Regex<Output>.RegexOutput> Returns a regular expression that uses the specified word boundary algorithm.
struct MatchThe result of matching a regular expression against a string.
Citizens in _StringProcessing
where Output == AnyRegexOutputMembers
init<OtherOutput>(Regex<OtherOutput>) Creates a regular expression with a dynamic capture list from the given regular expression.
init(String) throws Creates a regular expression from the given string, using a dynamic capture list.
Available in RegexBuilder
Members
init(() -> some RegexComponent<Output>) Creates a regular expression using a RegexBuilder closure.