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
to0
.$i -lt 3
sets the condition for the loop to continue. As long as$i
is less than3
, 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.
Instructions
Inside FOR_Example.ps1 create a for
loop that:
- initializes a counter
$i
to equal 1 - sets a run condition of
$i
is less than or equal to10
- increments
$i
by1
for each loop
Leave the body of the loop empty.
Inside the for
loop body, define a variable $square
and set it to:
$i * $i
Inside the for
loop body, use Write-Host
to output $square
. Feel free to use the following line of code:
Write-Host "The square of" $i "is" $square
Just be sure to output $square
. Your loop should run 10
times and output squares from 1 to 10.