The next type of control flow we will cover in this lesson is loops. Loops allow us to perform the same action multiple times within a script, whether outputting numerous messages to the user or processing data.

Loops define a body of code to be executed repeatedly until a stop condition is met. Each execution of code is called an iteration.

The first loop we will cover is the for loop. There are three steps to creating a for loop:

• initializing a counter variable
• setting a stop condition using the counter variable
• changing the value of the counter variable

The body of a for loop contains the code that iterates over and over until the given condition is met:

for ($i = 0; $i -lt 3; $i++) {
  Write-Host "i is ($i)"
}

The example above starts with the for keyword with the following inside the parentheses:

• $i = 0 initializes the counter $i to 0.
• $i -lt 3 sets the condition for the loop to continue. As long as $i is less than 3, the code inside the loop body will continue to execute
• $i++ increments the counter, so the set condition will eventually evaluate to false.

The above loop will repeat three times before $i -lt 3 is no longer true, and the code will output:

$i is 0
$i is 1
$i is 2

Once $i equals 3, the code will no longer execute.