Rename columns of a data frame by searching column name

Question

I am writing a wrapper to ggplot to produce multiple graphs based on various datasets. As I am passing the column names to the function, I need to rename the column names so tha

Answer 1

> names(df)[grep("^col", names(df))] <- 
                        paste("new", names(df)[grep("^col", names(df))], sep="_")
> names(df)
[1] "new_col1" "new_col2" "new_col3"

If you want to replace an ordered set of column names with an arbitrary character vector, then this should work:

names(df)[sapply(oldNames, grep, names(df) )] <- newNames

The sapply()-ed grep will give you the proper locations for the 'newNames' vector. I suppose you might want to make sure there are a complete set of matches if you were building this into a function.