Functions/Get-JaccardIndex.ps1
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function Get-JaccardIndex { <# .SYNOPSIS Get the Jaccard Index of two strings. .DESCRIPTION The Jaccard index, also known as the Jaccard similarity coefficient, measures similarity between finite sample sets, and is defined as the size of the intersection divided by the size of the union of the sample sets. .EXAMPLE Get-JaccardIndex 'karolin' 'kharolin' Calculate the Jaccard Index for the two strings. The output should be 0.875 .EXAMPLE Get-JaccardIndex (1,2,4) (2,4,6) Calculate the Jaccard Index for the two sets. The output should be 0.5 .LINK http://en.wikipedia.org/wiki/Jaccard_index https://communary.wordpress.com/ https://github.com/gravejester/Communary.PASM .NOTES Author: Øyvind Kallstad Date: 03.11.2014 Version: 1.0 Dependencies: Get-Intersection, Get-Union #> [CmdletBinding()] param ( [Parameter(Position = 0, Mandatory = $true)] [ValidateNotNullOrEmpty()] $a, [Parameter(Position = 1, Mandatory = $true)] [ValidateNotNullOrEmpty()] $b, # Makes matches case-sensitive. By default, matches are not case-sensitive. # This parameter is only applicable if the input are strings. [Parameter()] [switch] $CaseSensitive ) try { # verify both inputs are the same type if (-not ($a.GetType().Name -eq $b.GetType().Name)) { Write-Warning 'Both inputs need to be of the same type.' break } if ($a.GetType().Name -eq 'String') { if (-not($CaseSensitive)) { $a = $a.ToLower() $b = $b.ToLower() } $aArray = $a.ToCharArray() $bArray = $b.ToCharArray() } else { $aArray = $a $bArray = $b } # get intersection size and union size of both strings $intersectionSize = (Get-Intersection $aArray $bArray -CaseSensitive:$CaseSensitive).Length $unionSize = (Get-Union $aArray $bArray -CaseSensitive:$CaseSensitive).Length # calculate jaccard index by dividing union size with intersection size Write-Output ($intersectionSize / $unionSize) } catch { Write-Warning $_.Exception.Message } } |