Functions/Get-SorensenDiceCoefficient.ps1
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function Get-SorensenDiceCoefficient { <# .SYNOPSIS Get the Sorensen Dice Coefficient of two strings. .DESCRIPTION The Sørensen–Dice index, is a statistic used for comparing the similarity of two samples. .EXAMPLE Get-SorensenDiceCoefficient -String1 'night' -String2 'night' .LINK http://en.wikipedia.org/wiki/S%C3%B8rensen%E2%80%93Dice_coefficient https://communary.wordpress.com/ https://github.com/gravejester/Communary.PASM .NOTES Author: Øyvind Kallstad Date: 03.11.2014 Version: 1.0 Dependencies: Get-NGram, Get-Intersection #> [CmdletBinding()] param ( [Parameter(Position = 0, Mandatory)] [ValidateNotNullOrEmpty()] [string] $String1, [Parameter(Position = 1, Mandatory)] [ValidateNotNullOrEmpty()] [string] $String2, # Makes matches case-sensitive. By default, matches are not case-sensitive. [Parameter()] [switch] $CaseSensitive ) # handle case insensitivity if (-not($CaseSensitive)) { $String1 = $String1.ToLowerInvariant() $String2 = $String2.ToLowerInvariant() } $string1Bigrams = Get-NGram -String $String1 -Size 2 $string2Bigrams = Get-NGram -String $String2 -Size 2 $intersections = (Get-Intersection $string1Bigrams $string2Bigrams -CaseSensitive:$CaseSensitive).count Write-Output ([double](2 * $intersections) / [double]($string1Bigrams.count + $string2Bigrams.count)) } |