How to sum multiple items in an object in PowerShell?

Question

I have:

$report.gettype().name Object[]  echo $report  Item                       Average --                         ------- orange                     0.294117647058824 orange                    -0.901960784313726 orange                    -0.901960784313726 grape                      9.91335740072202 grape                      0 pear                       3.48736462093863 pear                      -0.0324909747292419 pear                      -0.0324909747292419 apple                     12.1261261261261 apple                     -0.0045045045045045 

I want to create a variable, $total, (such as a hash table) which contains the sum of the 'Average' column for each item, for example,

echo $total  orange  -1.5097 grape    9.913 pear     3.423 apple   12.116 

Right now I'm thinking of looping through the $report, but it's hell ugly, and I am looking for something more elegant than the following starting point (incomplete):

$tmpPrev = "" foreach($r in $report){     $tmp = $r.item     $subtotal = 0     if($tmp <> $tmpPrev){         $subtotal += $r.average     } 

How could I do this?

Answer 1

Cmdlets Group-Object and Measure-Object help to solve the task in a PowerShell-ish way:

Code:

# Demo input $report = @(     New-Object psobject -Property @{ Item = 'orange'; Average = 1 }     New-Object psobject -Property @{ Item = 'orange'; Average = 2 }     New-Object psobject -Property @{ Item = 'grape'; Average = 3 }     New-Object psobject -Property @{ Item = 'grape'; Average = 4 } )  # Process: group by 'Item' then sum 'Average' for each group # and create output objects on the fly $report | Group-Object Item | %{     New-Object psobject -Property @{         Item = $_.Name         Sum = ($_.Group | Measure-Object Average -Sum).Sum     } } 

Output:

Sum Item --- ----   3 orange   7 grape