break & next Functions in R for-loop (2 Examples)

 

This tutorial shows how to use the break and next commands within a for-loop in R.

Without further ado, let’s move directly to the examples!

 

Create Basic for-loop in R (without break or next)

In the examples of this tutorial, I’ll use the following for-loop as basement:

for(i in 1:5) {                     # Basic for-loop
  print(paste("This is step", i))
}

 

for-loop with basic R syntax

Figure 1: Basic Syntax of for-loop in R.

 

As you can see based on the previous figure, our example for-loop prints the words “This is step” and the running index i to the RStudio console.

Our loop runs from 1 to 5 and returns therefore five sentences. Let’s see what happens when we use break and next…

 

Example 1: break within for-loop

We can insert a break in our for-loop as shown in the following R code:

for(i in 1:5) {                     # for-loop with break
 
  if(i == 4) {
    break
  }
 
  print(paste("This is step", i))
}

 

R for-loop with break command

Figure 2: for-loop with break Function.

 

As shown in Figure 2, the loop stops (or “breaks”) when our running index i is equal to the value 4. For that reason, R returns only three sentences.

 

Example 2: next within for-loop

The next statement can be useful, in case we want to continue our loop after a certain break. The following R code skips step 4 of our loop, but continues again afterwards:

for(i in 1:5) {                     # for-loop with next
 
  if(i == 4) {
    next
  }
 
  print(paste("This is step", i))
}

 

for-loop with next command

Figure 3: for-loop with next Function.

 

Figure 3 shows the output after inserting the next function into our for-loop. R printed all steps beside step 4.

Note: The codes of the previous examples can also be applied to other types of loops (e.g. while loops).

 

Further Resources for the Handling of Loops

In case you want to learn more about for-loops in R, I can recommend the following YouTube video of Richard Webster’s channel:

 

 

In addition, you can have a look at the other R tutorials on my website:

This article explained how to apply break and next in the R programming language. Leave me a comment below in case you have any further questions.

 



 

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