Contents

firstMatch(in:)

Returns the first match for this regex found in the given substring.

Declaration

func firstMatch(in string: Substring) throws -> Regex<Output>.Match?

Parameters

  • string:

    The substring to match this regular expression against.

Return Value

The match, if one is found; otherwise, nil.

Discussion

Use the firstMatch(in:) method to search for the first occurrence of this regular expression in string. This example searches for the first sequence of digits that occurs in a string:

let digits = /[0-9]+/

if let digitsMatch = try digits.firstMatch(in: "The year is 2022; last year was 2021.") {
    print(digitsMatch.0)
} else {
    print("No match.")
}
// Prints "2022"

The firstMatch(in:) method can throw an error if this regex includes a transformation closure that throws an error.