str_extract Function in R (stringr Package)
In this tutorial, I’ll explain how to use the str_extract function to extract matching patterns from a character string in the R programming language.
Table of contents:
- Introduction of Example Data
- Example: Application of str_extract Function in R
- Video, Further Resources & Summary
Let’s start right away!
Introduction of Example Data
As a first step, we need to create an example string in R:
x <- "a simple example string" # Create example character string
As you can see, our example character string simply contains the sentence “a simple example string”. Now, let’s apply the str_extract function of the stringr package to this string…
Example: Application of str_extract Function in R
First, we need to install and load stringr:
install.packages("stringr") # Install stringr package library("stringr") # Load stringr package
After loading the R package, we can apply the str_extract function as follows:
str_extract(x, "exa") # Apply str_extract function # "exa"
Within the previous R code, we checked whether our example string x contains the pattern “exa”. Since our example string contains this character pattern, the str_extract returned the pattern to the RStudio console.
Let’s see what happens when we check for a non-existing pattern:
str_extract(x, "abc") # Different pattern # NA
Our example character string does not contain the character pattern “abc”. For that reason, the RStudio console returns NA.
Video, Further Resources & Summary
Do you need further information on the contents of this article? Then you could have a look at the following video of my YouTube channel. I’m explaining the R programming syntax of this post in the video instruction:
The YouTube video will be added soon.
Furthermore, you may want to have a look at the related tutorials of my website. A selection of tutorials about R programming can be found here:
- substr & substring Functions in R
- Extract First or Last n Characters from String in R
- nth, first & last Functions of dplyr Package
- R Functions List (+ Examples)
- The R Programming Language
In summary: In this R tutorial you learned how to extract matching patterns from a string with the str_extract function. If you have further comments or questions, don’t hesitate to let me know in the comments section below.
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