Mastering Windows PowerShell Scripting - Third Edition

Removing elements from the queue

Elements are removed from the end using the Dequeue method:

$queue.Dequeue() # This returns Tom. 

If the queue is empty and the Dequeue method is called, an error will be thrown, as shown here:

PS> $queue.Dequeue()Exception calling "Dequeue" with "0" argument(s): "Queue empty."At line:1 char:1+ $queue.Dequeue()+ ~~~~~~~~~~~~~~~~ + CategoryInfo : NotSpecified: (:) [], MethodInvocationException + FullyQualifiedErrorId : InvalidOperationException

To avoid this, the Count property of the queue may be inspected, for example:

# Set-up the queue $queue = New-Object System.Collections.Generic.Queue[String] "Tom", "Richard", "Harry" | ForEach-Object { $queue.Enqueue($_) } # Dequeue until the queue is empty while ($queue.Count ...