while loop in R

While loop in R programming language is used when the exact number of iterations of a loop is not known beforehand. It executes the same code again and again until a stop condition is met. While loop checks for the condition to be true or false n+1 times rather than n times. This is because the while loop checks for the condition before entering the body of the loop.

R- While loop Syntax: 

while (test_expression) { 

 statement update_expression }

How does a While loop execute? 

• Control falls into the while loop.
• The flow jumps to Condition
• Condition is tested. If the Condition yields true, the flow goes into the Body.
• If the Condition yields false, the flow goes outside the loop
• The statements inside the body of the loop get executed.
• Updation takes place.
• Control flows back to Step 2.
• The while loop has ended and the flow has gone outside.

Important Points about while loop in R language:

• It seems to be that while the loop will run forever but it is not true, condition is provided to stop it.
• When the condition is tested and the result is false then the loop is terminated.
• And when the tested result is True, then the loop will continue its execution.

# while loop example

#print mec 5 time

i=1

while (i<5){

    print("mec")

    i=i+1

    

}

output:

[1] "mec"

[1] "mec"

[1] "mec"

[1] "mec"

# while loop example

#sum of the digits of a number

n=5432

s=0

while (n!=0){

    d=n%%10

     s=s+d

    n=n%/%10

    

}

print(paste("sum of digits=",s))

output:

"sum of digits= 14"