Re: [R] Selecting rows according to a column

2009-10-28 Thread Peter Ehlers
William Dunlap wrote: -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Erik Iverson Sent: Wednesday, October 28, 2009 9:22 AM To: Gurpal Kalsi; r-help@r-project.org Subject: Re: [R] Selecting rows according to a column Hello

Re: [R] Selecting rows according to a column

2009-10-28 Thread Gurpal Kalsi
28, 2009 9:22 AM > > To: Gurpal Kalsi; r-help@r-project.org > > Subject: Re: [R] Selecting rows according to a column > > > > Hello, > > > > Here's an idea: > > > > ifelse(z$c == "a", z$a, z$b) > > If there may be many columns to select

Re: [R] Selecting rows according to a column

2009-10-28 Thread William Dunlap
> -Original Message- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of Erik Iverson > Sent: Wednesday, October 28, 2009 9:22 AM > To: Gurpal Kalsi; r-help@r-project.org > Subject: Re: [R] Selecting rows according to a column >

Re: [R] Selecting rows according to a column

2009-10-28 Thread Adaikalavan Ramasamy
Not very elegant but try: z <- data.frame(a = 1:5, b=10*(1:5), c = c("a", "a", "b", "b", "b") ) z[ cbind( 1:nrow(z), match( as.character(z$c) , colnames(z) ) ) ] If you have very few columns, you can use ifelse() too. Regards, Adai Gurpal Kalsi wrote: Hi, With a data such as: z = data.f

Re: [R] Selecting rows according to a column

2009-10-28 Thread Erik Iverson
> Subject: [R] Selecting rows according to a column > > Hi, > > With a data such as: > > z = data.frame(a = 1:5, b=10*a, c = c("a", "a", "b", "b", "b") ) > * a b c* > *1* 10 *a* > *2* 20 *a* > 3 *30* *b* > 4

[R] Selecting rows according to a column

2009-10-28 Thread Gurpal Kalsi
Hi, With a data such as: > z = data.frame(a = 1:5, b=10*a, c = c("a", "a", "b", "b", "b") ) * a b c* *1* 10 *a* *2* 20 *a* 3 *30* *b* 4 *40* *b* 5 *50* *b* Can anyone suggest a way to select [1, 2, 30, 40, 50], ie. using column "c" to specify which column is selected for each row. Many th