R can use regular expressions to crunch complex data patterns

Regular expressions are a programming tool that allows you to specify complex patterns to match and replace strings of text, and R has a powerful facility for using them.

Here’s a simple regular expression pattern that looks for the letter “a”. When you give this pattern to R, it’ll say whether there’s a match.

Regular expressions are the ultimate tool for cleaning up messy data. Lots of platforms and languages implement regular expressions, even though Excel doesn’t.