How to handle $null in the pipeline

Question

I often have the following situation in my PowerShell code: I have a function or property that returns a collection of objects, or $null. If you push the results in

Answer 1

If you can modify your function, have it return an empty collection/array instead of $null:

PS> function Empty { $null }
PS> Empty | %{'hi'}
hi

PS> function Empty { @() }
PS> Empty | %{'hi'}

Otherwise, go with what Oisin suggests although I would suggest a slight tweak:

filter Skip-Null { $_|?{ $_ -ne $null } } 

Otherwise this will also filter 0 and $false.

Update 4-30-2012: This issue is fixed in PowerShell v3. V3 will not iterate over a scalar $null value.