Store Results of Loop in Data Frame in R (Example) | Save while- & for-Loops

 

In this article you’ll learn how to save the results of a loop in a data frame in R.

The article will consist of this information:

If you want to learn more about these topics, keep reading:

 

Example: Saving output of for-Loop in Data Frame

This Example explains how to store the results of a for-loop in a data frame.

First, we have to create a data frame with the number of rows that our final data frame will have. The following R code creates such a data frame and fills the cells with NA values. This initial data frame needs to have only one column, since this data is overwritten later on.

data <- data.frame(NA_col = rep(NA, 3))     # Creating data containing NA
data                                        # Printing data
#   NA_col
# 1     NA
# 2     NA
# 3     NA

Now, we can write a for-loop that saves its results in our data frame. The following R code runs a for-loop with five iterations. In each iteration a new column is created, added to our data frame, and renamed.

for(i in 1:5) {                             # Head of for-loop
  new_col <- rep(i, 3)                      # Creating new variable
  data[ , i] <- new_col                     # Adding new variable to data
  colnames(data)[i] <- paste0("Col_", i)    # Renaming new variable
}

Have a look at the final output:

data                                        # Printing updated data
#   Col_1 Col_2 Col_3 Col_4 Col_5
# 1     1     2     3     4     5
# 2     1     2     3     4     5
# 3     1     2     3     4     5

As you can see based on the previous output of the RStudio console, we have created a data frame consisting of three rows and five numeric columns. Each column contains the output of one iteration of our for-loop.

Note that we could use the same type of R code within while-loops or repeat-loops.

 

Video & Further Resources

I have recently published a video on my YouTube channel, which illustrates the R syntax of the present post. You can find the video below.

 

The YouTube video will be added soon.

 

In addition, you might want to have a look at the other articles on my website. I have published several articles about loops in R already.

 

This page illustrated how to save for-loop outputs in data frames in R. In case you have any additional questions, let me know in the comments section below.

 



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