regexcite

“The goal of regexcite is to make regular expressions more exciting! It provides convenience functions to make some common tasks with string manipulation and regular expressions a bit easier.” ^ According to the tutorial I followed on r-pkgs.org anyways. This is mostly an identical reproduction of the code online.

Installation

You can install the development version of regexcite from GitHub with:

I personally recommend the official version given in the second line

# install.packages("devtools")
devtools::install_github("JWizards/regexcite")

devtools::install_github("jennybc/regexcite")

Usage

A fairly common task when dealing with strings is the need to split a single string into many parts. This is what base::strplit() and stringr::str_split() do.

(x <- "alfa,bravo,charlie,delta")
#> [1] "alfa,bravo,charlie,delta"
strsplit(x, split = ",")
#> [[1]]
#> [1] "alfa"    "bravo"   "charlie" "delta"
stringr::str_split(x, pattern = ",")
#> [[1]]
#> [1] "alfa"    "bravo"   "charlie" "delta"

Notice how the return value is a list of length one, where the first element holds the character vector of parts. Often the shape of this output is inconvenient, i.e. we want the un-listed version.

That’s exactly what regexcite::str_split_one() does.

library(regexcite)

str_split_one(x, pattern = ",")
#> [1] "alfa"    "bravo"   "charlie" "delta"

Use str_split_one() when the input is known to be a single string. For safety, it will error if its input has length greater than one.

str_split_one() is built on stringr::str_split(), so you can use its n argument and stringr’s general interface for describing the pattern to be matched.

str_split_one(x, pattern = ",", n = 2)
#> [1] "alfa"                "bravo,charlie,delta"

y <- "192.168.0.1"
str_split_one(y, pattern = stringr::fixed("."))
#> [1] "192" "168" "0"   "1"