You can use the following methods to count the number of TRUE values in a logical vector in R:

**Method 1: Use sum()**

sum(x, na.rm=TRUE)

This method will return the count of TRUE values in a vector.

**Method 2: Use summary()**

summary(x)

This method will return the count of TRUE, FALSE, and NA values in a vector.

The following examples show how to use each method in practice.

**Example 1: Count TRUE Values Using sum()**

The following code shows how to use **sum()** to count the number of TRUE values in a logical vector:

#create logical vector x <- c(TRUE, FALSE, FALSE, TRUE, FALSE, FALSE, NA, TRUE) #count TRUE values in vector sum(x, na.rm=TRUE) [1] 3

From the output we can see that there are **3** TRUE values in the vector.

**Note**: If there are NA values in the vector and we don’t use the argument **na.rm=TRUE**, then the function will return NA.

**Example 2: Count TRUE Values Using summary()**

The following code shows how to use **summary()** to count the number of TRUE, FALSE, and NA values in a logical vector:

#create logical vector x <- c(TRUE, FALSE, FALSE, TRUE, FALSE, FALSE, NA, TRUE) #count TRUE, FALSE, and NA values in vector summary(x) Mode FALSE TRUE NA's logical 4 3 1

From the output we can see:

- There are
**4**FALSE values in the vector. - There are
**3**TRUE values in the vector. - There is
**1**NA value in the vector.

The **summary()** function is particularly useful if you’d like to know the occurrence of each type of value in a logical vector.

If you’d like to only return the number of TRUE values from the** summary()** function, you can use the following syntax:

#create logical vector x <- c(TRUE, FALSE, FALSE, TRUE, FALSE, FALSE, NA, TRUE) #count TRUE values in vector summary(x)['TRUE'] TRUE 3

From the output we can see that there are **3** TRUE values in the vector.

**Additional Resources**

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

How to Count Values in Column with Condition in R

How to Count Observations by Group in R

How to Select Top N Values by Group in R