How to get values from dataframe's column conditional on other column

# test data
DF <- data.frame(X = 1:4, Y = c(TRUE, TRUE, FALSE, FALSE))

with(DF, X[Y]) # 1

DF$X[DF$Y]  # 2

DF[DF$Y, "X"] # 3

Sorry, that should be:

with(DF, X[Y,])

or

DF[DF$Y, "X"]

On 6/13/06, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:

If DF is your data.frame

with(DF, X[Y])

or

DF$X[DF$Y]



On 6/13/06, Yuri Volchik <volchik2000 at list.ru> wrote:

Hi to all members of this list,

I'm quite a novice to R and was wondering if there is a more elegant
way to solve a following problem:
Suppose we have a dataframe
 X     Y
.12   TRUE
-.24  TRUE
..     ...
.34   FALSE

i.e. two (or more columns) with data and we want to get vector of X
values conditional on Y values (say only X's when Y=TRUE).
Of course it is possible to do it by looping through the whole
dataframe, i was wondering if there is a a more elegant solution to
this in R?

--
Best regards,
 Yuri                            mailto:volchik2000 at list.ru