## E.4 Resources

Regular expressions are powerful tools, of course, but also a slippery slope on which computer-friendly folks can easily spend more time than anyone must know. Consider the clip in Figure E.4 a friendly warning:

### E.4.1 Background

For a proper definition, the historical background, and some key references on regular expressions:

### E.4.2 Learning and training

Many online sites offer tutorials and ways of trying out your regex skills:

### E.4.3 References

For using regular expressions in R:

• Evaluating ?base::regex provides documentation on Regular Expressions as used in R.

• See the back page of the RStudio cheatsheet on the stringr package and the cheatsheet on Basic Regular Expressions in R (contributed by Ian Kopacka):

[70_regex.Rmd updated on 2021-06-15 15:19:01 by hn.]