The **str_count()** function from the stringr package in R can be used to count the number of matches in a string.

This function uses the following syntax:

**str_count(string, pattern = “”)**

where:

**string:**Character vector**pattern:**Pattern to look for

The following examples show how to use this function in practice

**Example 1: Use str_count with One Pattern**

The following code shows how to use the **str_count()** function to count the number of times the letter ‘a’ occurs in each element in a character vector:

**library(stringr)
#create character vector
x <- c('Mavs', 'Cavs', 'Nets', 'Trailblazers', 'Heat')
#count number of times 'a' occurs in each element in vector
str_count(x, 'a')
[1] 1 1 0 2 1
**

Here’s how to interpret the output:

- The pattern ‘a’ occurs 1 time in ‘Mavs’
- The pattern ‘a’ occurs 1 time in ‘Cavs’
- The pattern ‘a’ occurs 0 times in ‘Nets’

And so on.

Note that **str_count()** is also case-sensitive, so a capital ‘A’ would return **0** for each element in the character vector.

**Example 2: Use ****str_count with Multiple Patterns**

The following code shows how to use the **str_count()** function to count the number of times the letter ‘a’ or the letter ‘s’ occurs in each element in a character vector:

**library(stringr)
#create character vector
x <- c('Mavs', 'Cavs', 'Nets', 'Trailblazers', 'Heat')
#count number of times 'a' or 's' occurs in each element in vector
str_count(x, 'a|s')
[1] 2 2 1 3 1
**

Here’s how to interpret the output:

- The pattern ‘a’ or ‘s’ occurs 2 times in ‘Mavs’
- The pattern ‘a’ or ‘s’ occurs 2 times in ‘Cavs’
- The pattern ‘a’ or ‘s’ occurs 1 time in ‘Nets’

**Note:** The **|** symbol represents an “OR” operator in R.

**Additional Resources**

The following tutorials explain how to perform other common tasks in R:

How to Use str_replace in R

How to Use str_split in R

How to Use str_detect in R