Loops

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Sriparno08
Published May 16, 2023Updated Apr 17, 2025
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Loops enable programs to execute the same set of statements multiple times until a stop condition is met. They are widely used for performing operations such as iterating through a list of files, processing user input, or automating repetitive tasks.

There are five types of loops in PowerShell:

  • for
  • foreach
  • while
  • do...while
  • do...until

for Loop

The PowerShell for loop executes the enclosed code until the given condition is met.

Syntax

for (<init>; <condition>; <repeat>) {
  <Statements>
}

Parameters:

  • <init>: Initializes a counter variable.
  • <condition>: Specifies the stop condition.
  • <repeat>: Increments/decrements the counter variable.

Example of for Loop

This example uses the PowerShell for loop to calculate squares of the numbers 1-5:

for ($i = 1; $i -le 5; $i++) {
  $square = $i * $i
  Write-Host "The square of" $i "is" $square
}

The output for the example will be:

The square of 1 is 1
The square of 2 is 4
The square of 3 is 9
The square of 4 is 16
The square of 5 is 25

foreach Loop

The foreach loop is specifically used for iterating over items in a collection or array.

Syntax

foreach ($<item> in $<collection>) {
  <Statements>
}

Parameters:

  • <item>: A variable for iterating the collection or array.
  • <collection>: The collection or array to iterate.

Example of foreach Loop

This example uses the foreach loop to check if the elements of an array are even or odd:

$array = 51, 12, 31, 4, 15


foreach ($element in $array) {
  if ($element % 2 -eq 0) {
    Write-Host $element "is" Even
  } else {
    Write-Host $element "is" Odd
  }
}

The output for the example will be:

51 is Odd
12 is Even
31 is Odd
4 is Even
15 is Odd

while Loop

The while loop executes statements repeatedly as long as the condition is True.

Syntax

while(<condition>) {
  <Statements>
}

Parameters:

  • <condition>: The condition to evaluate.

Example of while Loop

This example uses the while loop to increment numbers by 3 (starting from 0) and print them until count is less than 15:

$count = 0


while($count -lt 15) {
  $count += 3


  Write-Host The count is $count
}

The output for the example will be:

The count is 3
The count is 6
The count is 9
The count is 12
The count is 15

do...while Loop

The do...while loop is a slight variation of the while loop in which statements are executed once before the condition is checked.

Syntax

do {
  <Statements>
} while (<condition>)

Example of do...while Loop

This example uses the do...while loop to ask the user to guess the given number repeatedly until it’s guessed correctly:

$answer = 4


do {
  $input = Read-Host "Guess the number"
} while ($input -ne $answer)


Write-Host "Correct!"

The output for the example will be:

Guess the number: 2
Guess the number: 6
Guess the number: 4
Correct!

do...until Loop

The do...until loop is the same as the do...while loop except that the loop exits when the condition is True.

Syntax

do {
  <Statements>
} until (<condition>)

Example of do...until Loop

This example uses the do...until loop to print numbers starting from 1 until the count reaches 5:

$count = 1


do {
  Write-Output "Count is $count"


  $count++
} until ($count -eq 5)

The output for the example will be:

Count is 1
Count is 2
Count is 3
Count is 4

break and continue Statements

The break and continue statements are used for advanced loop control.

The break statement allows users to exit a loop before it ends.

This example uses the break statement to exit a loop when the count reaches 2:

for ($i = 0; $i -lt 5; $i++) {
  if ($i -eq 2) {
    break
  }


  Write-Host $i
}

The output for the example will be:

0
1

The continue statement allows users to skip the current iteration in a loop and move to the next one.

This example uses the continue statement to skip the iteration in the loop when the count is 4:

for ($i = 0; $i -le 5; $i++) {
  if ($i -eq 4) {
    continue
  }


  Write-Host $i
}

The output for the example will be:

0
1
2
3
5

PowerShell Loops: When to Use Each

Loop Type When to Use
for The number of iterations is known in advance or a counter-based loop is required.
foreach Iterating over items in a collection, array, or pipeline output is needed.
while The loop should continue as long as a specific condition remains true.
do...while The loop must run at least once and continue while a condition is true.
do...until The loop must run at least once and continue until a condition becomes true.

Frequently Asked Questions

1. Which loop is mostly used in PowerShell?

The foreach loop is mostly used in PowerShell, especially when working with arrays or collections, making scripts more readable and concise.

2. What is the difference between for and foreach loop in PowerShell?

The PowerShell for loop is used with a counter and is good for numeric iterations, whereas the foreach loop is used for looping through each item in a collection or array.

3. Which is faster, for or foreach?

In general, for can be slightly faster for simple numeric loops. However, foreach is often preferred for readability and simplicity when working with collections.

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