PowerShell: Comparing Object stored in an array result unequal

Question

In following code sample, the comparison of original object with its stored copy in an array results in unequal status. I want to understand this phenomena why they are not equal:

$MyArray=@()
$MyCFG="" | Select-Object -Property ProjName,ProCFG

$MyCFG.ProjName="p1"
$MyCFG.ProCFG="c1"
$MyArray+=$MyCFG.PsObject.Copy()

$MyCFG.ProjName="p2"
$MyCFG.ProCFG="c2"
$MyArray+=$MyCFG.PsObject.Copy()

$MyCFG.ProjName="p3"
$MyCFG.ProCFG="c3"
$MyArray+=$MyCFG.PsObject.Copy()


ForEach($obj in $MyArray)
{
    if ($MyCFG -eq $obj)
    {Write-Host "Equal"}
    else
    {Write-Host "Unequal"}

}

The last object values i.e. $MyCFG.ProjName="p3" and $MyCFG.ProCFG="c3" are supposed to be same as stored in $MyArray, but they results in Unequal as well.

Although, it can compare properly by comparing its property values i.e:

if (($MyCFG.ProjName -eq $obj.ProjName) -and ($MyCFG.ProCFG -eq $obj.ProCFG))

but wondering why Objects comparison results as unequal...

CB. · Accepted Answer · 2013-09-18 13:30:10Z

4

You can use compare-object in this way

ForEach($obj in $MyArray)
{ 
    if (compare-object $obj $mycfg -Property Projname,procfg)
    {Write-Host "Unequal"}
    else
    {Write-Host "Equal"}
}

Comparing the properties you need ( all in this case ) and test if there's some difference.

answered Sep 18, 2013 at 13:30

CB.

61.3k9 gold badges170 silver badges165 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Anthony Neace Over a year ago

+1 Another note for the OP: instead of explicitly writing the result to host, you could take advantage of Compare-Object not returning anything when it is true to return a boolean instead: @(Compare-Object $obj $MyCFG -Property projname,procfg).Length -eq 0

CB. Over a year ago

@HyperAnthony Try the code with my solution: there is not output from the compare-object in any conditions..

Anthony Neace Over a year ago

Right, it wasn't necessarily speaking to your example but I wanted to offer OP some usage advice for Compare-Object as they would hopefully follow-up on this answer by experimenting a bit with the cmdlet. (Like what would happen if it wasn't embedded in an if statement)

CB. Over a year ago

@HyperAnthony hu.. ok! My misunderstanding ;)

Eris Over a year ago

There are parameters to Compare-Object to tell it to output various combinations of Left-Only, Right-Only, or Both

Collectives™ on Stack Overflow

PowerShell: Comparing Object stored in an array result unequal

1 Answer 1

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related