Formatting Numbers (Part 2)

by Jan 30, 2018

In the previous tip we introduced the Get-DisplayFileSize function which automatically converts bytes to readable numbers with units such as “KB” and “MB”.

Using Select-Object, you can now produce folder listings with meaningful file sizes:

$Length = @{
    Name = "Length"
    Expression = { 
    if ($_.PSIsContainer) { return }
    $Number = $_.Length
    $newNumber = $Number
    $unit = 'Bytes,KB,MB,GB,TB,PB,EB,ZB' -split ','
    $i = 0
    while ($newNumber -ge 1KB -and $i -lt $unit.Length)
        $newNumber /= 1KB
    if ($i -eq $null) { $decimals = 0 } else { $decimals = 2 }
    $displayText = "'{0,10:N$decimals} {1}'" -f $newNumber, $unit[$i]
    $Number = $Number | Add-Member -MemberType ScriptMethod -Name ToString -Value ([Scriptblock]::Create($displayText)) -Force -PassThru
    return $Number
# pretty file sizes
dir $env:windir |
  Select-Object -Property Mode, LastWriteTime, $Length, Name |
  Sort-Object -Property Length

Note how the calculated property “Length” can still be sorted. It remains a byte value. Just the display text was changed.

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