Two seemingly equal ways of changing column names for R data.frame - only the other one works

Question

I have a dataframe and I need to add suffix to some of the variable names. In my case that\'s all numerical variables after spreading a variable to wide format. Could someone ex

Answer 1

Your fist command contains syntax errors. We can fix it to:

colnames(df[,2:ncol(df)]) <- paste0(names(df[,2:ncol(df)]), "_X")

That doesn't return an error, but still doesn't work. You assign column names to a subset of a data.frame, but that subset is never stored and the command doesn't change the names of the full data.frame.

You need to assign to a subset of the names:

colnames(df)[2:ncol(df)] <- paste0(names(df)[2:ncol(df)], "_X")