[Rd] subset() only returns first of equally named columns from a data.frame (PR#9733)

beierm at uni-duesseldorf.de beierm at uni-duesseldorf.de
Wed Jun 13 14:14:06 CEST 2007

Full_Name: Manfred Beier
Version: 2.5.0 (2007-04-23)
OS: linux-gnu
Submission from: (NULL) (

When multiple columns in a data.frame have the same name, only the first of them
is returned by the subset() function even when selected numerically.

> test <- data.frame(cbind(1,2,3))
> names(test) <- c("a","a","a")
> test
  a a a
1 1 2 3
> subset(test, TRUE, c(2,3))
  a a.1
1 1   1

For matrices subset() works correctly.

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