Powershell: GetType used in PowerShell, difference between variables

Question

What is the difference between variables $a and $b?

$a = (Get-Date).DayOfWeek $b = Get-Date | Select-Object DayOfWeek 

I tried to check

$a.GetType $b.GetType  MemberType          : Method OverloadDefinitions : {type GetType()} TypeNameOfValue     : System.Management.Automation.PSMethod Value               : type GetType() Name                : GetType IsInstance          : True  MemberType          : Method OverloadDefinitions : {type GetType()} TypeNameOfValue     : System.Management.Automation.PSMethod Value               : type GetType() Name                : GetType IsInstance          : True 

But there seems to be no difference although the output of these variables looks different.

Answer 1

First of all, you lack parentheses to call GetType. What you see is the MethodInfo describing the GetType method on [DayOfWeek]. To actually call GetType, you should do:

$a.GetType(); $b.GetType(); 

You should see that $a is a [DayOfWeek], and $b is a custom object generated by the Select-Object cmdlet to capture only the DayOfWeek property of a data object. Hence, it's an object with a DayOfWeek property only:

C:\> $b.DayOfWeek -eq $a True 

Answer 2

Select-Object creates a new psobject and copies the properties you requested to it. You can verify this with GetType():

PS > $a.GetType().fullname System.DayOfWeek  PS > $b.GetType().fullname System.Management.Automation.PSCustomObject