powershell - How to write a list sorted lexicographically in a grid listed by column?

Question

I have the result of Get-ChildItem, and I want to iterate over these, and display their names. By default if I simply use Write-Host then I get it listed out along the row like this:

PerfLogs  Program Files  Program Files (x86)  Python31  Temp  Users  Windows

However, say that I know I want it split into x columns, I want the output like this instead:

PerfLogs                  Python31     Windows
Program Files             Temp
Program Files (x86)       Users

As you can see, it lists it down the columns first, and then across.

Any idea how to get output like that? Ideally it would use the most # of columns as can fit on screen with the Name aligned to the left in each column.

UPDATE: thanks to Roman, I can now have my linux style 'ls' output with directory colors. Building off his updated script I have:

function color-ls
{
    dir $args | Format-High -Print {    
        $item = $args
        $fore = $host.UI.RawUI.ForegroundColor        
        $host.UI.RawUI.ForegroundColor = .{     
            if ($item[1].psIsContainer) {'Blue'}
            elseif ($item[1].Extension -match '.(exe|bat|cmd|ps1|psm1|vbs|rb|reg|dll|o|lib)') {'Red'}
            elseif ($item[1].Extension -match '.(zip|tar|gz|rar)') {'Yellow'}
            elseif ($item[1].Extension -match '.(py|pl|cs|rb|h|cpp)') {'Cyan'}
            elseif ($item[1].Extension -match '.(txt|cfg|conf|ini|csv|log|xml)') {'Green'}
            else {$fore}
        }
        write-host $args[0] -NoNewLine
        $host.UI.RawUI.ForegroundColor = $fore
    }
}

Output:

http://dl.dropbox.com/u/2809/lscolor.png

Answer 1

It’s an interesting idea and task.

UPDATE: the updated script contains a few fixes and improvements. It also allows to customize the output in several ways. See examples in the script comments.

Script Format-High.ps1:

<#
.SYNOPSIS
    Formats input by columns using maximum suitable column number.

.DESCRIPTION
    Format-High prints the specified property, expression, or string
    representation of input objects filling the table by columns.

    It is named in contrast to Format-Wide which prints by rows.

.EXAMPLE
    # just items
    ls c:windows | Format-High

    # ditto in colors based on PSIsContainer
    ls c:windows | Format-High -Print {$c = if ($args[1].PSIsContainer) {'yellow'} else {'white'}; Write-Host $args[0] -ForegroundColor $c -NoNewline}

    # just processes, not good
    ps | Format-High

    # process names, much better
    ps | Format-High Name

    # custom expression and width
    ps | Format-High {$_.Name + ':' + $_.WS} 70

    # process names in colors based on working sets
    ps | Format-High Name 70 {$c = if ($args[1].WS -gt 10mb) {'red'} else {'green'}; Write-Host $args[0] -ForegroundColor $c -NoNewline}
#>

param
(
    [object]$Property,
    [int]$Width = $Host.UI.RawUI.WindowSize.Width - 1,
    [scriptblock]$Print = { Write-Host $args[0] -NoNewline },
    [object[]]$InputObject
)

# process the input, get strings to format
if ($InputObject -eq $null) { $InputObject = @($input) }
if ($Property -is [string]) { $strings = $InputObject | Select-Object -ExpandProperty $Property }
elseif ($Property -is [scriptblock]) { $strings = $InputObject | ForEach-Object $Property }
else { $strings = $InputObject }
$strings = @(foreach($_ in $strings) { "$_" })

# pass 1: find the maximum column number
$nbest = 1
$bestwidths = @($Width)
for($ncolumn = 2; ; ++$ncolumn) {
    $nrow = [Math]::Ceiling($strings.Count / $ncolumn)
    $widths = @(
        for($s = 0; $s -lt $strings.Count; $s += $nrow) {
            $e = [Math]::Min($strings.Count, $s + $nrow)
            ($strings[$s .. ($e - 1)] | Measure-Object -Maximum Length).Maximum + 1
        }
    )
    if (($widths | Measure-Object -Sum).Sum -gt $Width) {
        break
    }
    $bestwidths = $widths
    $nbest = $ncolumn
    if ($nrow -le 1) {
        break
    }
}

# pass 2: print strings
$nrow = [Math]::Ceiling($strings.Count / $nbest)
for($r = 0; $r -lt $nrow; ++$r) {
    for($c = 0; $c -lt $nbest; ++$c) {
        $i = $c * $nrow + $r
        if ($i -lt $strings.Count) {
            & $Print ($strings[$i].PadRight($bestwidths[$c])) $InputObject[$i]
        }
    }
    & $Print "`r`n"
}