R repeat Loop
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.
We use the R repeat loop to execute a code block multiple times. However, the repeat loop doesn't have any condition to terminate the lYou can use the repeat
loop in R to execute a block of code multiple times. However, the repeat
loop does not have any condition to terminate the loop. You need to put an exit condition implicitly with a break
statement inside the loop.
The syntax of repeat
loop is:
repeat { # statements if(stop_condition) { break } }
Here, we have used the repeat
keyword to create a repeat
loop. It is different from the for
and while
loop because it does not use a predefined condition to exit from the loop.
Example 1: R repeat Loop
Let's see an example that will print numbers using a repeat
loop and will execute until the break
statement is executed.
x = 1 # Repeat loop repeat { print(x) # Break statement to terminate if x > 4 if (x > 4) { break } # Increment x by 1 x = x + 1 }
Output
[1] 1 [1] 2 [1] 3 [1] 4 [1] 5
Here, we have used a repeat
loop to print numbers from 1
to 5
. We have used an if
statement to provide a breaking condition which breaks the loop if the value of x
is greater than 4
.
Example 2: Infinite repeat Loop
If you fail to put a break
statement inside a repeat
loop, it will lead to an infinite loop. For example,
x = 1 sum = 0 # Repeat loop repeat { # Calculate sum sum = sum + x # Print sum print(sum) # Increment x by 1 x = x + 1 }
Output
[1] 1 [1] 3 [1] 6 [1] 10 . . .
In the above program, since we have not included any break
statement with an exit condition, the program prints the sum of numbers infinitely.
Example 3: repeat Loop with next Statement
You can also use a next
statement inside a repeat
loop to skip an iteration. For example,
x = 1 repeat { # Break if x = 4 if ( x == 4) { break } # Skip if x == 2 if ( x == 2 ) { # Increment x by 1 and skip x = x + 1 next } # Print x and increment x by 1 print(x) x = x + 1 }
Output
[1] 1 [1] 3
Here, we have a repeat
loop where we break the loop if x
is equal to 4
. We skip the iteration where x
becomes equal to 2
.
R-bloggers.com offers daily e-mail updates about R news and tutorials about learning R and many other topics. Click here if you're looking to post or find an R/data-science job.
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.