Get-FastLookup.ps1
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function Get-FastLookup { <# .SYNOPSIS Lookup a value in an array faster than Where-Object .DESCRIPTION Improve the speed of looking up a value in an array by creating a hashtable index. Good for looking up results in very large arrays or CSV files (e.g Import-Csv) .NOTES Version: 1.0 Author: Miles Gratz Creation Date: April 10, 2017 Purpose/Change: Initial script development .PARAMETER Array A mandatory parameter specifying the array used to create a 'FastLookup' (hashtable index) .PARAMETER Table A mandatory parameter specifying the 'FastLookup' created by New-FastLookup .PARAMETER Value A mandatory parameter specifying the search criteria (e.g. "Server458") .OUTPUTS The object(s) in the array that match the search .EXAMPLE PS> $array = 1..10000000 PS> $hashtable = New-FastLookup $array PS> Measure-Command { $array | Where-Object { $_ -eq 199999 } } Days : 0 Hours : 0 Minutes : 0 Seconds : 9 Milliseconds : 306 PS> Measure-Command { Get-FastLookup -Value 199999 -Array $array -Table $hashtable } Days : 0 Hours : 0 Minutes : 0 Seconds : 0 Milliseconds : 65 [NOTE] Performance test on Windows 10 x64 (i5-6200U, 8GB RAM, SSD) #> param( [Parameter(Mandatory=$true)] $Value, [Parameter(Mandatory=$true)] [Array]$Array, [Parameter(Mandatory=$true)] [Hashtable]$Table ) Try { # Lookup Value in hashtable $Index = $Table[$Value] # Find quantity of Index values $IndexQty = ($Index -split ",").Count # Find objects in Array based on Index # (if multiple, split into array) If ($IndexQty -eq 1){ $Array[$Index] } If ($IndexQty -ge 2){ $Array[$Index -split ","] } } Catch { $null } } |