Prevent ArrayList.Add() from returning the index

You can cast to void to ignore the return value from the Add method:

[void]$myArrayList.Add("test")

Another option is to redirect to $null:

$myArrayList.Add("test") > $null

Two more options :)

Pipe to out-null

$myArrayList.Add("test") | Out-Null

Assign the result to $null:

$null = $myArrayList.Add("test")

Related