Looping

for / foreach / while / do…while / do…until / Flow control

for

Syntax

:loop_label for (initialization; condition; increment) {
    statement_block
}

Example

PS> $array = 1..3
PS> for ($i = 0; $i -lt $array.Count; $i++) {
>>     Write-Host ($array[$i] * 2)
>> }
>>
2
4
6

foreach

Syntax

:loop_label foreach (variable in expression) {
    statement_block
}

Example

PS> $array = 1..3
PS> foreach ($item in $array) {
>>     Write-Host ([Math]::Pow($item,2))
>> }
>>
1
4
9

while

Syntax

:loop_label while (condition) {
    statement_block
}

Example

PS> $command = ""
PS> while ($command -notmatch "quit") {
>>     $command = Read-Host "Enter your Command"
>> }
>>
Enter your Command: a
Enter your Command: quit
PS>

do…while

Syntax

# do...while
:loop_label do {
    statement_block
} while (condition)

Example

PS> $command = ""
PS> do {
>>     $command = Read-Host "Please quit"
>> } while ($command -ne "quit")
>>
Please quit: a
Please quit: quit
PS>

do…until

Syntax

# do...until
:loop_label do {
    statement_block
} until (condition)

Example

PS> $command = ""
PS> do {
>>     $command = Read-Host "Please quit"
>> } until ($command -ne 'quit')
>>
Please quit: quit
Please quit: a
PS>

Flow control

Without a label, simply exit the inner loop.

:outer while(conditions){
    while(conditions){
        if(conditions){break}
    }
}

With a label, it exits the loop with the label.

:outer while(conditions){
    while(conditions){
        if(conditions){break outer}
    }
}

Example　Without label

PS> $array = 1..3
PS> $limit = $array[-1]
PS> :outer foreach ($y in $array) {
>>     foreach ($x in $array) {
>>         if ($x -eq $limit) {
>>             Write-Host "limit break"
>>             break
>>         }
>>         Write-Host $x $y
>>     }
>> }
>>
1 1
2 1
limit break
1 2
2 2
limit break
1 3
2 3
limit break

Example　With label

PS> $array = 1..3
PS> $limit = $array[-1]
PS> :outer foreach ($y in $array) {
>>     foreach ($x in $array) {
>>         if ($x -eq $limit) {
>>             Write-Host "limit break"
>>             break outer # Different here!
>>         }
>>         Write-Host $x $y
>>     }
>> }
>>
1 1
2 1