Count NA Values in R (3 Examples)
In this R tutorial you’ll learn how to determine the number of NA values in a vector or data frame column.
The page is structured as follows:
- Example 1: Count NA Values in Vector
- Example 2: Count NA Values in Data Frame Column
- Example 3: Count NA Values in All Data Frame Columns
- Video & Further Resources
Let’s start right away…
Example 1: Count NA Values in Vector
Example 1 shows how to determine the amount of NA values in a vector.
First, we have to create an example vector with NA values:
vec <- c(3, 1, NA, 3, NA, NA, 4) vec # 3 1 NA 3 NA NA 4
As you can see, our example vector contains several numeric values and NAs. If we want to count the number of NA values in our example vector, we can use a combination of the sum and is.na functions:
sum(is.na(vec)) # 3
After running the previous code, the RStudio console returns the value 3, i.e. our example vector contains 3 NA values.
Example 2: Count NA Values in Data Frame Column
We can apply a similar R syntax as in Example 1 to determine the number of NA values in a data frame column. First, we need to create some example data:
data <- data.frame(x1 = c(NA, 5, 5, NA, 1, 2), x2 = c(1, 2, 3, NA, 5, 6), x3 = 1) data # x1 x2 x3 # 1 NA 1 1 # 2 5 2 1 # 3 5 3 1 # 4 NA NA 1 # 5 1 5 1 # 6 2 6 1
Our example data consists of six rows and three columns. The variables x1 and x2 contain NA values.
Let’s assume that we want to extract the amount of NA values on the variable x1. Then, we can use the following R code:
sum(is.na(data$x1)) # 2
The variable x1 contains 2 NAs.
Example 3: Count NA Values in All Data Frame Columns
We can also count the NA values of multiple data frame columns by using the colSums function instead of the sum function. Have a look at the following R code:
colSums(is.na(data)) # x1 x2 x3 # 2 1 0
The RStudio console output shows the number of NA values for each of our variables. The variable x1 contains 2 NA values, the variable x2 contains 1 NA value, and the variable x3 contains no NA values.
Video & Further Resources
Have a look at the following video of my YouTube channel. I’m explaining the R syntax of this tutorial in the video.
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Furthermore, you could have a look at some of the other articles which I have published on my website. Some articles can be found below:
- What are NA Values?
- is.na Function in R
- sum Function in R
- colSums, rowSums, colMeans & rowMeans in R
- The R Programming Language
To summarize: At this point you should know how to different ways how to count NA values in vectors, data frame columns, and variables in the R programming language. Please let me know in the comments section, in case you have any additional questions and/or comments.
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dear sir, your video is really helpful, could you please tell me how to take percentage column wise for the NA values
Thank you, glad you like the tutorial!
You can calculate NA percentages by column using the following R code:
Thank you very much, very helpful
Thanks Kathie, glad you found it useful! 🙂