How to Use Repeat Loop in R: Syntax and Examples

In R, a repeat loop runs code repeatedly until you explicitly stop it using break. It has no built-in condition, so you must use break inside the loop to exit it.

Syntax

The repeat loop syntax in R is simple. You write repeat followed by curly braces {} containing the code to repeat. To stop the loop, use break inside the braces when a condition is met.

• repeat: starts the loop
• { }: contains the code block to repeat
• break: exits the loop when called

r

repeat {
  # code to repeat
  if (condition) {
    break
  }
}

Example

This example shows a repeat loop that counts from 1 to 5 and then stops using break.

r

count <- 1
repeat {
  print(count)
  if (count >= 5) {
    break
  }
  count <- count + 1
}

Output

[1] 1
[1] 2
[1] 3
[1] 4
[1] 5

Common Pitfalls

A common mistake is forgetting to include a break statement, which causes an infinite loop that never stops. Always ensure your loop has a clear exit condition.

Wrong way (infinite loop):

r

count <- 1
repeat {
  print(count)
  count <- count + 1
  # Missing break condition
}

Quick Reference

• repeat: starts an infinite loop
• break: stops the loop
• Use if inside loop to check exit condition
• Always include break to avoid infinite loops

Key Takeaways

Use repeat to run code repeatedly until you use break to stop.

Always include a break condition inside the loop to avoid infinite loops.

The repeat loop has no built-in exit condition; you control when it stops.

Use if statements inside the loop to decide when to break.

The repeat loop is useful when you want to loop until a condition is met but don’t know how many times in advance.