extract: Extract Elements from a Named Object
In Kmisc: Kevin Miscellaneous

Description Usage Arguments Details See Also Examples

Extracts elements from an R object with the names attribute set in a 'lazy' way. The first argument is the object, while the second is a set of names parsed from .... We return the object, including only the elements with names matched from ....

1	extract(x, ...)

`x`	An R object with a `names` attribute.
`...`	an optional number of 'names' to match in `dat`.

We can be 'lazy' with how we pass names. The names passed to ... are not evaluated directly; rather, their character representation is taken and used for extraction.

without, extract.re

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)