Rdatatable/data.table — pull request #912 by matthieugomez (2014-10-23 21:41:40+00:00)
Title: regex + wildcard

I should have continued my previous pull request #817, but I'm not how to do it since I used a different fork.

````R
N=10;
set.seed(1)
DT <- data.table(
id = sample(5, N, TRUE),
v1 = sample(5, N, TRUE),
v2 = sample(5, N, TRUE)
)
DT[,.SD, .SDcols = w("v*")]
DT[,.SD, .SDcols = w("v*", "v*")]
DT[,.SD, .SDcols = w("v*", "id")]

DT[,.SD, .SDcols = -w("v*")]
DT[,.SD, .SDcols = -r("^v.*")]
DT[,.SD, .SDcols = r("^v[a-z]")]
DT[,.SD, .SDcols = -r("^v[a-z]")]
````