## E.4 Resources

Regular expressions are powerful tools, of course, but also a topic that computer-friendly folks can easily spend more time on than anyone must know. Consult the following links for additional resources on regular expressions.

### E.4.1 Background

For a proper definition, the historical background, and 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

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

• See the back page of the RStudio cheatsheet on the stringr package (Wickham, 2019b) and the cheatsheet on Basic Regular Expressions in R (contributed by Ian Kopacka):

[70_regex.Rmd updated on 2020-11-20 16:56:16 by hn.]

### References

Wickham, H. (2019b). stringr: Simple, consistent wrappers for common string operations. Retrieved from https://CRAN.R-project.org/package=stringr