PowerShell: Loop, Iteration

By Xah Lee. Date: . Last updated: .

Cmdlet: ForEach-Object

ForEach-Object Cmdlet is most useful when you need to pipe to it. The input can be any collection type.

syntax:

ForEach-Object ScriptBlock 

Get-ChildItem | ForEach-Object {$_.fullname}

Statement: Foreach

foreach-statement is useful when you want to go thru all the values of a collection.

foreach statement must be on a single line, when used in PowerShell prompt.

$aa = 1..9
foreach ($x in $aa) { Write-Host $x }
# prints 1 to 9

Statement: For

for-statement is useful if you also need the index of the collection.

$aa = 0..9
for ($i=0; $i -le $aa.length; $i=$i+1) { $aa[$i] }
# prints 0 to 9

Statement: While

while-statement is most useful if you need to test a condition before the loop.

$a = 0..9
$i=5
while($i -lt 10) {
  $a[$i]; $i++
}
# prints 5 to 9

PowerShell: Loop, Iteration