lgrep: Convenience versions of grep

In Epi: Statistical Analysis in Epidemiology

Convenience versions of grep

Description

Often you want the elements of a vector (or its names or levels) that meet a certain pattern. But grep only gives you the position, so these functions are designed to give you that.

Usage

fgrep( pattern, x, ... )
ngrep( pattern, x, ... )
lgrep( pattern, x, ... )

Arguments

pattern	Pattern searched for.
x	Object where pattern is searched. Or in whose names or levels attributes pattern is sought.
...	Arguments passed on to grep.

Value

Elements of the input x (fgrep) or its names attribute (ngrep) or levels attribute (lgrep).

Author(s)

Bendix Carstensen, [e-mail], http://bendixcarstensen.com

See Also

grep

Examples

ff <- factor( ll <- paste( sample( letters[1:3], 20, replace=TRUE ),
                           sample( letters[1:3], 20, replace=TRUE ), sep="" ) )
ff
fgrep( "a", ff )
fgrep( "a", ll )
ngrep( "a", ff )
lgrep( "a", ff )
lgrep( "a", ff, invert=TRUE )

Epi documentation built on Oct. 1, 2024, 5:07 p.m.