How to delete Identical columns
Hi, Katherine, IF the naming scheme of the columns of your data frame is consistently <stringwithoutdot> and <stringwithoutdot.number> if duplicated columns appear THEN (something like) df[ -grep( "\\.", names( df))] could help. (But it's maybe more efficient to avoid - a priori - producing duplicated columns, if the data frame is large, as you say.) Regards -- Gerrit
On Thu, 28 Mar 2013, Katherine Gobin wrote:
Dear R forum
Suppose I have a data.frame
df = data.frame(id = c(1:6), x = c(15, 21, 14, 21, 14, 38), y = c(36, 38, 55, 11, 5, 18), x.1 = c(15, 21, 14, 21, 14, 38), z = c("D", "B", "A", "F", "H", "P"))
df
? id? x? y??? x.1 z 1? 1 15 36? 15 D 2? 2 21 38? 21 B 3? 3 14 55? 14 A 4? 4 21 11? 21 F 5? 5 14? 5? 14 H 6? 6 38 18? 38 P Clearly columns x and x.1 are identical. In reality, I have a large data.frame and can't make out which columns are identical, but I am sure that column with name say x is repeated as x.1, x.2 etc. How to automatically identify and retain only one column (in this example column x) among the identical columns besides other non-identical columns (viz. id, y and z). Regards Katherine