subset

The main advantage of subset() over [() is that you only mention the name of the data.frame once

x <- data.frame(xin=c(1, 8, 16, 1, 8, 16), xout=c(14, 5, 884, 14, 5, 884))
 
subset(x, xin > 7, select = xout) # not x$xin > 7
   xout
 2    5
 3  884
 5    5
 6  884

Really Handy Hint: subset treats NA's as FALSE. ( %in% also does this)

SeeAlso