Substitute

type	returns
Method	string

Arguments

name	type	description
value	regex | string	The regex to perform replacements on
replacement	string | (...matches) -> string	Replacement for each matches location

Explanation

Matches all occurences of value, with replacement.

value

• If value is a string. It is matched as appears in the string gloablly, it is not converted to a regular expression.

• A regular expression's capture groups are passed to the replacement if applicable.

String replacements

If the replacement is a string, the following charcater sequences have special behavior:

name	explanation	example
$\$	Inserts a literal $	"$\$59.99"
$&	Refers to the entire matches string	"( $& )"
$n	Where n is a number, refers to the nth capture group	$2, $1
$`	Refers to the match the precedes the given match	encountered: $`
$'	Refers to the match that follows the given match	upcoming: $'

Function replacements

If the replacement is a function, the capture groups are passed in the format ( c1, c2, ..., cn ). The function should return string, otherwise an error will be thrown

Examples

"1 + 1 = 2".sub(/\d+ ([+*/-]) \d/g, "$1") == "+ = 2"
"1 + 1 - 2".sub(/(\d+ )?([+-]) \d+/g, "$'") == " - 2 "
"Hi".sub("i", "ello") == "Hello"