First, use RegexBuddy to define a regex or retrieve a regexp saved in a RegexBuddy library. Rely on RegexBuddy's clear regex analysis, which is constantly updated as you build the pattern, rather than dealing with the cryptic regex syntax on your own. Detailed help on that syntax is always only a click away.
If you copied a regex written for another programming language, simply paste it into RegexBuddy, select the original language, and then convert the regex to the specific version of R you're using. If you're writing a code library that needs to work with multiple versions of R, compare your regex between those R versions to make sure it will work exactly the same with all of them. RegexBuddy knows exactly which regex features are available in R 2.14.0 through R 3.5.1.
If you created a new regular expression, test and debug it in RegexBuddy before using it in your R code. Test each regex in RegexBuddy's safe sandbox without risking precious data. Quickly apply the regex to a wide variety of input and sample data, without having to produce that input through your statistical package.
Finally, let RegexBuddy generate a source code snippet that you can copy and paste directly into the R IDE or your favorite R code editor. Just choose what you want to use the regex for, and a fully functional code snippet is ready. You can change the names of variables and parameters to suit your naming style or the current situation, which RegexBuddy automatically remembers.
Don't bother trying to remember the R function calls and the parameters they require. And don't worry about properly escaping backslashes and quotes. Just tell RegexBuddy what you want to do, and you will get the proper R code straight away.