Kmisc (version 0.1.0)

extract: Extract Variables from a List / Data Frame

Description

Extract variables from a list / data.frame. The first argument is the list / data.frame, while the second is passed to and parsed from .... We return the list / data.frame, including only those whose names were found in ....

Usage

extract(dat, ...)

Arguments

dat

list or data.frame object, or other similar object with a names attribute

...

an optional number of 'names' to match in dat

Details

We can be 'lazy' with how we name the variables. The names passed to ... are not evaluated directly; rather, their character representation is taken and used for extraction. Furthermore, for a given item submitted, all text before a $ is removed.

See Also

without extract.re

Examples

dat <- data.frame( x = c(1, 2, 3), y = c("a", "b", "c"), z=c(4, 5, 6) )
## all of these return identical output
dat[ names(dat) %in% c("x","z") ]
extract( dat, x, z)
extract( dat, dat$x, dat$z )