caroline (version 0.5.0)

m: Regexp Match Operator

Description

A grep sub like function that actually returns the n back-referenced *matches* (as columns in a datframe of the same length as the input vector). This function is more geared towards *extracting* than cleaning ... even though it uses sub (a cleaning function) to do so.

Usage

m(pattern, vect, names="V", types="character")

Arguments

pattern

A regular expression pattern with at least one back reference.

vect

A string or vector of strings one which to apply the pattern match.

names

The vector of names of the new variables to be created out of vect. Must be the same length as vect.

types

The vector of types of the new variables to be created out of vect. Must be the same lenght as vect.

See Also

gsub,regexpr, grep, gregexpr.

Examples

## single vector output examples
m(pattern="asdf.([A-Z]{4}).", vect=c('asdf.AS.fds','asdf.ABCD.asdf', '12.ASDF.asdf','asdf.REWQ.123'))


Rurls <- c('http://www.r-project.org',    'http://cran.r-project.org',
           'http://journal.r-project.org','http://developer.r-project.org')
m(pattern="http://([a-z]+).r-project.org", vect=Rurls)


# dataframe output examples

data(mtcars)
m(pattern="^([A-Za-z]+) ?(.*)$", vect=rownames(mtcars), names=c('make','model'), types=rep('character',2))