Format-Columns.ps1

Format-Columns.ps1

function Format-Columns {
################################################################
#.Synopsis
#  Formats incoming data to columns.
#.Description
#  It works similarly as Format-Wide but it works vertically. Format-Wide outputs
#  the data row by row, but Format-Columns outputs them column by column.
#.Parameter Property
#  Name of property to get from the object.
#  It may be 
#   -- string - name of property.
#   -- scriptblock
#   -- hashtable with keys 'Expression' (value is string=property name or scriptblock)
#      and 'FormatString' (used in -f operator)
#.Parameter Column
#  Count of columns
#.Parameter Autosize
#  Determines if count of columns is computed automatically.
#.Parameter MaxColumn
#  Maximal count of columns if Autosize is specified
#.Parameter InputObject
#  Data to display
#.Example
#  PS> 1..150 | Format-Columns -Autosize
#.Example 
#  PS> Format-Columns -Col 3 -Input 1..130
#.Example
#  PS> Get-Process | Format-Columns -prop @{Expression='Handles'; FormatString='{0:00000}'} -auto
#.Example
#  PS> Get-Process | Format-Columns -prop {$_.Handles} -auto
#.Notes
# Name: Get-Columns
# Author: stej, http://twitter.com/stejcz
# Lastedit: 2010-01-18
# Version 0.3 - 2010-01-18
#  - fixed for Posh ISE
# Version 0.2 - 2010-01-14
#  - added MaxColumn
#  - fixed bug - displaying collection of 1 item was incorrect
# Version 0.1 - 2010-01-06
################################################################
	param(
		[Parameter(Mandatory=$false,Position=0)][Object]$Property,
		[Parameter()][switch]$Autosize,
		[Parameter(Mandatory=$false)][int]$Column,
		[Parameter(Mandatory=$false)][int]$MaxColumn,
		[Parameter(Mandatory=$true,ValueFromPipeline=$true)][PsObject[]]$InputObject
	)
	begin   { $values = @() }
	process { $values += $InputObject }
	end {
		function ProcessValues {
			$ret = $values
			$p = $Property
			if ($p -is [Hashtable]) {
				$exp = $p.Expression
				if ($exp) {
					if ($exp -is [string])          { $ret = $ret | % { $_.($exp) } }
					elseif ($exp -is [scriptblock]) { $ret = $ret | % { & $exp $_} }
					else                            { throw 'Invalid Expression value' }
				}
				if ($p.FormatString) {
					if ($p.FormatString -is [string]) {	$ret = $ret | % { $p.FormatString -f $_ } }
					else {                              throw 'Invalid format string' }
				}
			}
			elseif ($p -is [scriptblock]) { $ret = $ret | % { & $p $_} }
			elseif ($p -is [string]) {      $ret = $ret | % { $_.$p } }
			elseif ($p -ne $null) {         throw 'Invalid -property type' }
			# in case there were some numbers, objects, etc., convert them to string
			$ret | % { $_.ToString() }
		}
		function Base($i) { [Math]::Floor($i) }
		function Max($i1, $i2) {  [Math]::Max($i1, $i2) }
		if (!$Column) { $Autosize = $true }
		$values = ProcessValues
		
		$valuesCount = @($values).Count
		if ($valuesCount -eq 1) {
			$values | Out-Host
			return
		}
		
		# from some reason the console host doesn't use the last column and writes to new line
		$consoleWidth          = `
			if (gi variable:psise -ea silentlycontinue) { $Host.UI.RawUI.BufferSize.Width }
			else                                        { $Host.UI.RawUI.maxWindowSize.Width -1; }
		$spaceWidthBetweenCols = 2
			
		# get length of the longest string
		$values | % -Begin { [int]$maxLength = -1 } -Process { $maxLength = Max $maxLength $_.Length }
		
		# get count of columns if not provided
		if ($Autosize) {
			$Column         = Max (Base ($consoleWidth/($maxLength+$spaceWidthBetweenCols))) 1
			$remainingSpace = $consoleWidth - $Column*($maxLength+$spaceWidthBetweenCols);
			if ($remainingSpace -ge $maxLength) { 
				$Column++ 
			}
			if ($MaxColumn -and $MaxColumn -lt $Column) {
				Write-Debug "Columns corrected to $MaxColumn (original: $Column)"
				$Column = $MaxColumn
			}
		}
		$countOfRows       = [Math]::Ceiling($valuesCount / $Column)
		$maxPossibleLength = Base ($consoleWidth / $Column)
		
		# cut too long values, considers count of columns and space between them
		$values = $values | % { 
			if ($_.length -gt $maxPossibleLength) { $_.Remove($maxPossibleLength-2) + '..' }
			else { $_ }
		}
		
		#add empty values so that the values fill rectangle (2 dim array) without space
		if ($Column -gt 1) {
			$values += (@('') * ($countOfRows*$Column - $valuesCount))
		}
		# in case there is only one item, make it array
		$values = @($values)
		<#
		now we have values like this: 1, 2, 3, 4, 5, 6, 7, ''
		and we want to display them like this:
		1 3 5 7
		2 4 6 ''
		#>
		
		$formatString = (1..$Column | %{"{$($_-1),-$maxPossibleLength}"}) -join ''
		1..$countOfRows | % { 
			$r    = $_-1
			$line = @(1..$Column | % { $values[$r + ($_-1)*$countOfRows]} )
			$formatString -f $line | Out-Host
		}
	}
}