[R] How to retrieve a column name of a data frame

2012-02-02 Thread ikuzar
Hi, I 'd like to know how to retrieve a column name of a data frame. For instance : df = data.frame(c1=c('a','b'),c2=c(1,2)) df c1 c2 1 a 1 2 b 2 I would like to retrieve the column name which value is 2 (here, the column is c2) thanks for your help -- View this message in context:

Re: [R] How to retrieve a column name of a data frame

2012-02-02 Thread R. Michael Weylandt
colnames(df)[2] Michael On Thu, Feb 2, 2012 at 10:31 AM, ikuzar raz...@hotmail.fr wrote: Hi, I 'd like to know how to retrieve a column name of a data frame. For instance : df = data.frame(c1=c('a','b'),c2=c(1,2)) df  c1 c2 1  a  1 2  b  2 I would like to retrieve the column name

Re: [R] How to retrieve a column name of a data frame

2012-02-02 Thread Rainer Schuermann
colnames( df )[2] [1] c2 On Thursday 02 February 2012 07:31:33 ikuzar wrote: Hi, I 'd like to know how to retrieve a column name of a data frame. For instance : df = data.frame(c1=c('a','b'),c2=c(1,2)) df c1 c2 1 a 1 2 b 2 I would like to retrieve the column name

Re: [R] How to retrieve a column name of a data frame

2012-02-02 Thread ikuzar
Sorry, it was not clear: my program have to return column name corresponding to a value, for example 'b' (so, the corresponding column is c1) How to retrieve c1 ? Thanks -- View this message in context:

Re: [R] How to retrieve a column name of a data frame

2012-02-02 Thread R. Michael Weylandt
I'd use something like which(df == b, arr.ind = TRUE) which, gives the column number in the second spot; this gives you colnames(df)[which(df == b, arr.ind = TRUE)[2]] Michael On Thu, Feb 2, 2012 at 11:00 AM, ikuzar raz...@hotmail.fr wrote: Sorry, it was not clear: my program have to