Compare-Object - Separate side columns

Question

Is it possible to display the results of a PowerShell Compare-Object in two columns showing the differences of reference vs difference objects?

For example

Answer 1

Possible? Sure. Feasible? Not so much. PowerShell wasn't really built for creating this kind of tabular output. What you can do is collect the differences in a hashtable as nested arrays by input file:

$ht = @{}
Compare-Object $Base $Test | ForEach-Object {
  $value = $_.InputObject
  switch ($_.SideIndicator) {
    '=>' { $ht['Test'] += @($value) }
    '<=' { $ht['Base'] += @($value) }
  }
}

then transpose the hashtable:

$cnt  = $ht.Values |
        ForEach-Object { $_.Count } |
        Sort-Object |
        Select-Object -Last 1
$keys = $ht.Keys | Sort-Object

0..($cnt-1) | ForEach-Object {
  $props = [ordered]@{}
  foreach ($key in $keys) {
    $props[$key] = $ht[$key][$_]
  }
  New-Object -Type PSObject -Property $props
} | Format-Table -AutoSize

To include the item count in the header name change $props[$key] to $props["$key($($ht[$key].Count))"].