PowerShell array initialization

Here's two more ways, both very concise.

$arr1 = @(0) * 20
$arr2 = ,0 * 20

You can also rely on the default value of the constructor if you wish to create a typed array:

> $a = new-object bool[] 5
> $a
False
False
False
False
False

The default value of a bool is apparently false so this works in your case. Likewise if you create a typed int[] array, you'll get the default value of 0.

Another cool way that I use to initialze arrays is with the following shorthand:

> $a = ($false, $false, $false, $false, $false)
> $a
False
False
False
False
False

Or if you can you want to initialize a range, I've sometimes found this useful:

> $a = (1..5)   
> $a
1
2
3
4
5

Hope this was somewhat helpful!

Yet another alternative:

for ($i = 0; $i -lt 5; $i++) 
{ 
  $arr += @($false) 
}

This one works if $arr isn't defined yet.

NOTE - there are better (and more performant) ways to do this... see https://stackoverflow.com/a/234060/4570 below as an example.

$array = 1..5 | foreach { $false }

$array = @()
for($i=0; $i -lt 5; $i++)
{
    $array += $i
}

The solution I found was to use the New-Object cmdlet to initialize an array of the proper size.

$array = new-object object[] 5 
for($i=0; $i -lt $array.Length;$i++)
{
    $array[$i] = $FALSE
}

If I don't know the size up front, I use an arraylist instead of an array.

$al = New-Object System.Collections.ArrayList
for($i=0; $i -lt 5; $i++)
{
    $al.Add($i)
}

Here's another typical way:

$array = for($i = 0; $i -le 4; $i++) { $false }

Or try this an idea. Works with powershell 5.0+.

[bool[]]$tf=((,$False)*5)

$array = foreach($i in 1..5) { $false }