Count Number of Occurrences of Certain Character in String in R (2 Examples)

In this tutorial you’ll learn how to get the number of times a specific character occurs in a string in the R programming language.

The page looks as follows:

• Introduction of Example Data
• Example 1: Count Character with Base R
• Example 2: Count Character with stringr Package
• Video, Further Resources & Summary

It’s time to dive into the R syntax:

Introduction of Example Data

We’ll use the following character string as basement for the examples of this R programming tutorial:

x <- "ajdvmaamfsjdaaa"
x
# "ajdvmaamfsjdaaa"

Our example string contains a random sequence of characters.

Example 1: Count Character with Base R

Example 1 shows how to count the number of occurrences of a specific letter using the functions of the basic installation of the R programming language. More precisely, we are applying the lengths, regmatches, and gregexpr functions:

lengths(regmatches(x, gregexpr("a", x)))
# 6

The RStudio console returns the value 6, i.e. our string contains the character a 6 times.

Example 2: Count Character with stringr Package

As you have seen in Example 1, we can count the occurrence of a character with the basic functions of the R programming language. However, the stringr package provides a much simpler solution. First, we need to install and load the package:

install.packages("stringr")
library("stringr")

Now, we can apply the str_count function to get the same result as in Example 1:

str_count(x, "a")
# 6

Video, Further Resources & Summary

In case you need further info on the R programming codes of this tutorial, you may want to have a look at the following video of my YouTube channel. I’m explaining the R programming code of this article in the video.

In addition, I can recommend to have a look at the other posts of this homepage. You can find a selection of tutorials below:

• str_count Function in R
• stringr Package in R
• The R Programming Language

In this tutorial, I showed how to how to calculate the number of occurrences of a certain character in a string in R programming. Let me know in the comments section below, in case you have further questions.