Re: [R] tapply to data.frame or matrix

41 1.V42 1.V43 1.V44 1.V51 1.V52 1.V53 1.V54  #   9    10    11    12    13    14    15    16    17    18    19    20 A.K. - Original Message - From: Rui Barradas To: Jannis Cc: r-help Sent: Tuesday, September 4, 2012 11:30 AM Subject: Re: [R] tapply to data.frame or matrix Hello,

Re: [R] tapply to data.frame or matrix

Hello, Here's a way. test <- as.data.frame(matrix(1:20, ncol = 5, nrow=4)) test.ind <- c(1,1,2,2,2) lapply(split(colnames(test), test.ind), function(x) unlist(test[, x])) Hope this helps, Rui Barradas Em 04-09-2012 15:40, Jannis escreveu: Dear R users, imagine i have a dataframe and an ind

[R] tapply to data.frame or matrix

Dear R users, imagine i have a dataframe and an indexing vector with the length of the amount of columns of the dataframe. Is there any convenient way to combine the colums of the dataframe into vectors (or straight away apply fundtions to these subsets) according to the indexing vector in a