RVerbalExpressions

The goal of RVerbalExpressions is to make it easier to construct regular expressions. Grammar and functionality inspired by VerbalExpressions, this is essentially another port using the R programming language. Usage of %>% is encouraged to build expressions in a chain like fashion.

There are a couple of functions missing from the original JSVerbalExpressions:

  1. replace isn’t included because there are numerous R functions for this, gsub being one example
  2. add is a utility function for appending expressions to one another and isn’t included because we use %>% for that

Others just haven’t made it yet, see here.

Installation

You can install RVerbalExpressions from GitHub with:

Example

This is a basic example which shows you how to build a regular expression:

library(RVerbalExpressions)

# construct an expression
x <- start_of_line() %>% 
  then('http') %>% 
  maybe('s') %>% 
  then('://') %>% 
  maybe('www.') %>% 
  anything_but(' ') %>% 
  end_of_line()

x
#> [1] "^(?:http)(?:s)?(?:\\://)(?:www\\.)?(?:[^ ]*)$"

grepl(x, "https://www.google.com")
#> [1] TRUE

Other Implementations

You can see an up to date list of all ports on VerbalExpressions.github.io.

Additionally, there is another R package rex by @kevinushey that tries to solve the same problem. I encourage you to check it out!

Contributing

If you find any issues, please file an issue or submit a PR. All contributions are welcome! See the list of todo items here if you’re looking for something to specific to work on.