Apply Function to Every Row of Data Using dplyr Package in R | rowwise Function Explained
This task can be done with the rowwise function and, hence, this article contains one examples for this function. More precisely, the article contains the following information:
- Construction of Example Data
- Example: Apply rowwise Function of dplyr Package in R
- Video & Further Resources
If you want to know more about these contents, keep reading:
Construction of Example Data
First, we need to install and load the dplyr package to R:
install.packages("dplyr") # Install and load dplyr library("dplyr")
Furthermore, we need to create some example data as basement for the example:
data <- as.tbl(data.frame(x1 = 1:5, # Create example data x2 = 2:6, x3 = 3:7)) data # Print data to console # # A tibble: 5 x 3 # x1 x2 x3 # <int> <int> <int> # 1 1 2 3 # 2 2 3 4 # 3 3 4 5 # 4 4 5 6 # 5 5 6 7
Our example data consists of five rows and three numeric columns. Note that we are using a tibble in this example. However, we could also apply the following R code to a data frame.
Example: Apply rowwise Function of dplyr Package in R
If we want to apply a function to each row of a data table, we can use the rowwise function of the dplyr package in combination with the mutate function. Have a look at the following R syntax:
data %>% # Apply rowwise function rowwise() %>% mutate(row_sum = sum(x1, x2, x3)) # # A tibble: 5 x 4 # x1 x2 x3 row_sum # <int> <int> <int> <int> # 1 1 2 3 6 # 2 2 3 4 9 # 3 3 4 5 12 # 4 4 5 6 15 # 5 5 6 7 18
As you can see based on the output of the RStudio console, we just created a new tibble with an additional variable row_sum, containing the row sums of each row of our data matrix.
In other words: We applied the sum function to each row of our tibble. However, we could use any other function instead of the sum function.
Video & Further Resources
Do you need further explanations on the content of this article? Then you might watch the following video of my YouTube channel. I illustrate the R programming codes of this article in the video:
Furthermore, you could have a look at some of the related R programming posts of my homepage:
- Apply Function to Every Row of Data Frame or Matrix in Base R
- mutate & transmute R Functions of dplyr Package
- dplyr Package in R
- R Functions List (+ Examples)
- The R Programming Language
To summarize: In this article you learned how to use an R command for each row of a data table using the dplyr package of the R programming language. If you have any additional comments and/or questions, don’t hesitate to tell me about it in the comments section below.