R Repeat

The R Repeat executes the statements inside the code block multiple number times. Repeat loop in R programming doesn’t provide any condition to check so, we have to give the condition to exit from repeat loop. In this article, we show you how to use Repeat in R Programming with example. Before we get into the case, let us see the syntax of R repeat.

R Repeat loop Syntax

The syntax of the While loop in R Programming language is

repeat  {
    statement 1
    statement 2
    ………….
    statement N
    # Please provide Condition to exit or use Break Statement
}
#This statement is from Outside the Repeat Loop

First, it will execute the statements inside the loop, and if there are any loop breaking statements, then it will exit from the loop.

R Repeat Flow Chart

The following picture will show you the flow chart behind the R Repeat

R Repeat Flow Chart

R repeat Flow chart sequence is:

  1. First, we initialize our variables. Next, it will enter into the Repeat loop.
  2. It will execute the group of statements inside the loop.
  3. Next, we have to use any expression inside the loop to exit.
  4. Now it will check for the condition. If the condition is True, then it executes the Break statement exit from the loop.
  5. If the condition is False, then the statements inside the R Repeat loop executed again.

R Repeat Loop example

This program helps us to understand the Repeat in R Programming. It allows the user to enter an integer value below 10. Using this value, it adds those values up to 10.

# R Repeat Loop Example

total <- 0
number <- as.integer(readline(prompt="Please Enter any integer Value below 10:  "))

repeat  {
  total = total + number
  number = number + 1
  if (number > 10)  {
    break
  }
}

print(paste("The total Sum of Numbers From the Repeat Loop is:  ", total))

In this R Programming example, We are going to enter number = 7. It means total = 7 + 8 + 9 + 10 = 34

R Repeat Loop 1

Within the following statements, First, we declared the total variable and assigned it to Zero. Next, it will ask the user to enter any integer value below 10, and we are assigning the user entered value to a number variable.

total <- 0
number <- as.integer(readline(prompt="Please Enter any integer Value below 10:  "))

Next line, we used the While loop, and the expression inside the While loop will make sure that the given number is less than or equal to 10.

repeat  {
  total = total + number
  number = number + 1
}

In this R repeat example, User Entered value: number = 7 and we initialized the total = 0

First Iteration

  • total = total + number
  • total = 0 + 7 ==> 7

Next, number will be incremented by 1 (number = number + 1). Please refer R Arithmetic Operators article to understand this + notation.

Second Iteration

Within the first Iteration, the values of both the number and total changed as number = 8 and total = 7

  • total = total + number
  • total = 7 + 8 ==> 15

Next, number incremented by 1.

R Repeat Third Iteration

Within the second Iteration, the values of both the number and total changed as number = 9 and total = 15

  • total = total + number
  • total = 15 + 9 ==> 24

Next, number = number + 1

Fourth Iteration

Within the third Iteration, the values of both the number and total changed as number = 10 and total = 24

  • total = total + number
  • total = 24 + 10 ==> 34

Next, number = number + 1

Here, Number = 11, and the condition present inside the If Statement (number > 10) is True. So, the Break statement executed and it will exit from the loop

 if (number > 10)  {
    break
  }

The last print statement print the total sum of digits present in the given number as output.

print(paste("The total Sum of Numbers From the While Loop is:  ", total))

Infinite Repeat in R Programming

If you forgot to use the Conditions or Break statement to terminate the R Repeat loop, then statements inside the loop executed infinite times (also called as an infinite loop).

# Infinite Repeat R Loop Example

total <- 0
number <- as.integer(readline(prompt="Please Enter any integer Value:  "))

repeat  {
  total = total + number
  number = number + 1
  print(number)
}
R Repeat Loop 2

In this R repeat example, there is no condition to check or no break statement to break the loop, so repeat loop will go on executing the statements infinite times. Now, let us add the Break statement inside the If statement.

# R Repeat Loop Example

total <- 0
number <- as.integer(readline(prompt="Please Enter any integer Value below 10:  "))

repeat  {
  total = total + number
  number = number + 1
  if (number > 15)  {
    break
  }
  print(number)
}

Now, when it reaches 15, the condition will fail. Let us see the output

R Repeat Loop 3