Get-FastLookup.ps1
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function Get-FastLookup { <# .SYNOPSIS Designed to optimize the speed of searching an array. .DESCRIPTION Improve the speed of looking up a value in an array by creating a hashtable index. Good for looping through very large arrays or CSV files .NOTES Version: 1.2 Author: Miles Gratz Creation Date: April 20, 2017 Purpose/Change: Improve examples .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..1000000 $hashtable = New-FastLookup -Array $array Get-FastLookup -Value 2017 -Array $array -Table $hashtable .EXAMPLE PS> # Search for thousand random numbers in an array of one million $array = 1..1000000 $search = 1..1000 | ForEach-Object { Get-Random -Maximum $array.Count } --------------------------------------------------------------- Where-Object Performance Test Measure-Command { $array | Where-Object { $_ -in $search } } Minutes : 2 Seconds : 39 Milliseconds : 658 --------------------------------------------------------------- ForEach Performance Test Measure-Command { foreach ($item in $array){ if ($item -in $search){ $item } } } Minutes : 1 Seconds : 27 Milliseconds : 460 --------------------------------------------------------------- FastLookup Performance Test Measure-Command { $hashtable = New-FastLookup -Array $array foreach ($item in $search){ Get-FastLookup -Value $item -Array $array -Table $hashtable } } Minutes : 0 Seconds : 49 Milliseconds : 933 --------------------------------------------------------------- [NOTE] Performance test on Windows 10 x64 (i5-6200U/8GB/SSD) #> param( [Parameter(Mandatory=$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 } } |