Count property of array in PowerShell with pscustomobjects - powershell

Question

If the array has only one CustomObjects and the Count property is null. Why?
If use only strings, the Count property is one.
function MyFunction
{
$Objects = #()
$Objects += [pscustomobject]#{Label = "Hallo"}
# $Objects += [pscustomobject]#{Label = "World"}
$Objects
}
$objs = MyFunction
Write-Host "Count: $($objs.Count)"
Output: "Count: " because $objs.Count is null
function MyFunction
{
$Objects = #()
$Objects += [pscustomobject]#{Label = "Hallo"}
$Objects += [pscustomobject]#{Label = "World"}
$Objects
}
$objs = MyFunction
Write-Host "Count: $($objs.Count)"
Output: "Count: 2"
Behavior is different if I add strings
function MyFunction
{
$Objects = #()
$Objects += "Hallo"
# $Objects += [pscustomobject]#{Label = "World"}
$Objects
}
$objs = MyFunction
Write-Host "Count: $($objs.Count)"
Output: "Count: 1"

Answer 1

You can force the function to return an array even if the nested array is constructed of one object.
function MyFunction
{
$Objects = #()
$Objects += [pscustomobject]#{Label = "Hallo"}
# $Objects += [pscustomobject]#{Label = "World"}
return ,$Objects
}
That comma makes an explicit conversion to an array even if the supplied $Objects is already an array of more than one object. This forces a construction of an array with one element. Outside, Powershell does unboxing of a one-item array, so you'll get an array if there was one, so this method works around default Powershell behavior for working with one-item arrays. You experience Count being 1 because in Powershell 3.0 Microsoft fixed one-item arrays by adding Count property to every object so that indexing of one object returns Count as 1, and for $null zero is returned, but the PSCustomObjects are excluded from this as a natural reason declares that they can contain their own Count properties, thus no default Count property is included for a custom object. That's why you don't get Count if there's only one object.
The behavior of , can be seen on the following example:
function hehe {
$a=#()
$a+=2
$a+=4
$b=,$a
write-verbose $b.count # if a variable is assigned ",$a", the value is always 1
return ,$a
}
Output:
PS K:> (hehe).count
VERBOSE: 1
2