Functions/Get-Soundex.ps1
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function Get-Soundex { <# .SYNOPSIS Get the soundex code of a string. .DESCRIPTION Soundex is a phonetic algorithm for indexing names by sound, as pronounced in English. The goal is for homophones to be encoded to the same representation so that they can be matched despite minor differences in spelling. The algorithm mainly encodes consonants; a vowel will not be encoded unless it is the first letter. .EXAMPLE Get-Soundex 'Tymczak' .LINK http://en.wikipedia.org/wiki/Soundex https://communary.wordpress.com/ https://github.com/gravejester/Communary.PASM .NOTES Author: Øyvind Kallstad Date: 03.11.2014 Version: 1.0 #> [CmdletBinding()] param ( [Parameter(Position = 0, Mandatory)] [string] $String ) # convert to upper case and strip of illegal characters $String = $String.ToUpper() $String = [regex]::Replace($String, '[^\w\s]', [System.String]::Empty) $maxSoundexLength = 4 $previousWasHorW = $false $soundex = New-Object System.Text.StringBuilder # soundex always starts with the first letter of the string [void]$soundex.Append($String[0]) for ($i = 1; $i -lt $String.Length; $i++) { $soundexNumberForCurrentCharacter = ConvertTo-SoundexNumber $String[$i] # don't add 0s as these are not part of the soundex if ($soundexNumberForCurrentCharacter -ne 0) { # if soundex same as previous, don't add if ($soundexNumberForCurrentCharacter -eq (ConvertTo-SoundexNumber $String[($i -1)])) { continue } # two letters with the same number separated by 'h' or 'w' are coded as a single number if (($i -gt 2) -and ($previousWasHorW) -and ($soundexNumberForCurrentCharacter -eq (ConvertTo-SoundexNumber ($String[$i-2])))) { continue } [void]$soundex.Append($soundexNumberForCurrentCharacter) } $previousWasHorW = @('H','W') -contains $String[$i] } $soundexNumberForFirstChar = ConvertTo-SoundexNumber $String[0] # remove same numbers adjacent at the start of the soundex Write-Output (($soundex[0] + ($soundex.ToString().Substring(1)).TrimStart("$soundexNumberForFirstChar")).PadRight($maxSoundexLength, '0').Substring(0, $maxSoundexLength)) } function ConvertTo-SoundexNumber { param([char]$Char) $a1 = @('B','F','P','V') $a2 = @('C','G','J','K','Q','S','X','Z') $a3 = @('D','T') $a4 = @('L') $a5 = @('M','N') $a6 = @('R') # convert char to soundex number switch ($Char) { {$a1 -contains $_} {$soundexNumber = 1;break} {$a2 -contains $_} {$soundexNumber = 2;break} {$a3 -contains $_} {$soundexNumber = 3;break} {$a4 -contains $_} {$soundexNumber = 4;break} {$a5 -contains $_} {$soundexNumber = 5;break} {$a6 -contains $_} {$soundexNumber = 6;break} DEFAULT {$soundexNumber = 0} } Write-Output $soundexNumber } |