r - split character data into numbers and letters

Question

I have a vector of character data. Most of the elements in the vector consist of one or more letters followed by one or more numbers. I wish to split each element in the vector into the character portion and the number portion. I found a similar question on Stackoverflow.com here:

split a character from a number with multiple digits

However, the answer given above does not seem to work completely in my case or I am doing something wrong. An example vector is below:

my.data <- c("aaa", "b11", "b21", "b101", "b111", "ccc1", "ddd1", "ccc20", "ddd13")

# I can obtain the number portion using:
gsub("[^[:digit:]]", "", my.data)

# However, I cannot obtaining the character portion using:
gsub("[:digit:]", "", my.data)

How can I obtain the character portion? I am using R version 2.14.1 on a Windows 7 64-bit machine.

Answer 1

For your regex you have to use:

gsub("[[:digit:]]","",my.data)

The [:digit:] character class only makes sense inside a set of [].