Storing Variables in ForEach Loop

Question

I have a large dataset of seasonal ratings for many pieces of equipment. Each piece of equipment currently has 3 data objects, in order: Summer>Winter>(Spring & Fall). I want to condense this so each piece of equipment only has one line of ratings.

$Equipment|%{if($_.C100_SP -match "Winter"){$aW=$_.A100_SU,$bW=$_.B100_SU,$cW=$_.C100_SU}elseif($_.C100_SP -match "Summer"){$aS=$_.A100_SU,$bS=$_.B100_SU,$cS=$_.C100_SU}elseif($_.C100_SP -match "Spring"){$_.A100_SP=$_.A100_F=$_.A100_SU;$_.B100_SP=$_.B100_F=$_.B100_SU;$_.C100_SP=$_.C100_F=$_.C100_SU;$_.A100_SU=$aS;$_.B100_SU=$bS;$_.C100_SU=$cS;$_.A100_W=$aW;$_.B100_W=$bW;$_.C100_W=$cW;$_.A='x'}}|Where-Object{$_.A -eq 'x'}

This code attempts to store the summer and winter ratings as variables ($aW, $bS, etc.), insert them into the spring record, then filter so only the filled out records are left. However, the winter and fall variables keep passing $null to the output, along with 9999, a common placeholder in this dataset.

A100_SP    : 4219
B100_SP    : 4219
C100_SP    : 9999
A100_SU    : {9999, $null}
B100_SU    : 
C100_SU    : 
A100_F     : 4219
B100_F     : 4219
C100_F     : 9999
A100_W     : {9999, $null}
B100_W     : 
C100_W     :

The Spring and fall values are working, which makes me think this is a problem with storing variables between iterations, but I can't find much help on the web.

Any ideas how to get those variables to stay put?

woxxom · Accepted Answer · 2016-10-07 01:11:46Z

The wrong statement separation in the first if clause: ,. It should be ;
Nothing was pushed down the pipeline: there should be $_ at the end of Spring case.
Instead of Where simply don't output anything to the pipeline in Winter and Summer .

$Equipment | %{
    switch -regex ($_.C100_SP) {
        "Winter" {
            $aW = $_.A100_SU
            $bW = $_.B100_SU
            $cW = $_.C100_SU
            break
        }
        "Summer" {
            $aS = $_.A100_SU
            $bS = $_.B100_SU
            $cS = $_.C100_SU
            break
        }
        "Spring" {
            $_.A100_SP = $_.A100_F = $_.A100_SU
            $_.B100_SP = $_.B100_F = $_.B100_SU
            $_.C100_SP = $_.C100_F = $_.C100_SU
            $_.A100_SU = $aS
            $_.B100_SU = $bS
            $_.C100_SU = $cS
            $_.A100_W = $aW
            $_.B100_W = $bW
            $_.C100_W = $cW
            $_
        }
    }
}

P.S. Don't use one-liners if you can't write them with your eyes closed :-)

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