Returns a substring enclosed by two regular expression patterns.
By default returns the name of the arguments being indexed by
squared brackets ([]
) in a string containing an expression.
Arguments
- x
A character string.
- left
A character string. Regular expression to serve as look ahead.
- right
A character string. Regular expression to serve as a look behind.
- rm_left
An integer. Number of bites after left-side match to remove from result. Defaults to -1.
- rm_right
An integer. Number of bites after right-side match to remove from result. Defaults to 0.