snippets/microsoft/ms-office/excel/functions/FuzzyMatch.vba

Option Explicit
Type RankInfo
    Offset As Integer
    Percentage As Single
End Type

Function FuzzyPercent(ByVal String1 As String, _
                      ByVal String2 As String, _
                      Optional Algorithm As Integer = 3, _
                      Optional Normalised As Boolean = False) As Single
'*************************************
'** Return a % match on two strings **
'*************************************
Dim intLen1 As Integer, intLen2 As Integer
Dim intCurLen As Integer
Dim intTo As Integer
Dim intPos As Integer
Dim intPtr As Integer
Dim intScore As Integer
Dim intTotScore As Integer
Dim intStartPos As Integer
Dim strWork As String

'-------------------------------------------------------
'-- If strings havent been normalised, normalise them --
'-------------------------------------------------------
If Normalised = False Then
    String1 = LCase$(Application.Trim(String1))
    String2 = LCase$(Application.Trim(String2))
End If

'----------------------------------------------
'-- Give 100% match if strings exactly equal --
'----------------------------------------------
If String1 = String2 Then
    FuzzyPercent = 1
    Exit Function
End If

intLen1 = Len(String1)
intLen2 = Len(String2)

'----------------------------------------
'-- Give 0% match if string length < 2 --
'----------------------------------------
If intLen1 < 2 Then
    FuzzyPercent = 0
    Exit Function
End If

intTotScore = 0                   'initialise total possible score
intScore = 0                      'initialise current score
'Taken from: http://www.mrexcel.com/forum/excel-questions/195635-fuzzy-matching-new-version-plus-explanation.html

'--------------------------------------------------------
'-- If Algorithm = 1 or 3, Search for single characters --
'--------------------------------------------------------
If (Algorithm And 1) <> 0 Then
    FuzzyAlg1 String1, String2, intScore, intTotScore
    If intLen1 < intLen2 Then FuzzyAlg1 String2, String1, intScore, intTotScore
End If

'-----------------------------------------------------------
'-- If Algorithm = 2 or 3, Search for pairs, triplets etc. --
'-----------------------------------------------------------
If (Algorithm And 2) <> 0 Then
    FuzzyAlg2 String1, String2, intScore, intTotScore
    If intLen1 < intLen2 Then FuzzyAlg2 String2, String1, intScore, intTotScore
End If

FuzzyPercent = intScore / intTotScore

End Function
Private Sub FuzzyAlg1(ByVal String1 As String, _
                      ByVal String2 As String, _
                      ByRef Score As Integer, _
                      ByRef TotScore As Integer)
Dim intLen1 As Integer, intPos As Integer, intPtr As Integer, intStartPos As Integer

intLen1 = Len(String1)
TotScore = TotScore + intLen1              'update total possible score
intPos = 0
For intPtr = 1 To intLen1
    intStartPos = intPos + 1
    intPos = InStr(intStartPos, String2, Mid$(String1, intPtr, 1))
    If intPos > 0 Then
        If intPos > intStartPos + 3 Then     'No match if char is > 3 bytes away
            intPos = intStartPos
        Else
            Score = Score + 1          'Update current score
        End If
    Else
        intPos = intStartPos
    End If
Next intPtr
End Sub
Private Sub FuzzyAlg2(ByVal String1 As String, _
                        ByVal String2 As String, _
                        ByRef Score As Integer, _
                        ByRef TotScore As Integer)
Dim intCurLen As Integer, intLen1 As Integer, intTo As Integer, intPtr As Integer, intPos As Integer
Dim strWork As String

intLen1 = Len(String1)
For intCurLen = 2 To intLen1
    strWork = String2                          'Get a copy of String2
    intTo = intLen1 - intCurLen + 1
    TotScore = TotScore + Int(intLen1 / intCurLen)  'Update total possible score
    For intPtr = 1 To intTo Step intCurLen
        intPos = InStr(strWork, Mid$(String1, intPtr, intCurLen))
        If intPos > 0 Then
            Mid$(strWork, intPos, intCurLen) = String$(intCurLen, &H0) 'corrupt found string
            Score = Score + 1     'Update current score
        End If
    Next intPtr
Next intCurLen

End Sub

Function FuzzyVLookup(ByVal LookupValue As String, _
                      ByVal TableArray As Range, _
                      ByVal IndexNum As Integer, _
                      Optional NFPercent As Single = 0.05, _
                      Optional Rank As Integer = 1, _
                      Optional Algorithm As Integer = 3, _
                      Optional AdditionalCols As Integer = 0) As Variant
'********************************************************************************
'** Function to Fuzzy match LookupValue with entries in                        **
'** column 1 of table specified by TableArray.                                 **
'** TableArray must specify the top left cell of the range to be searched      **
'** The function stops scanning the table when an empty cell in column 1       **
'** is found.                                                                  **
'** For each entry in column 1 of the table, FuzzyPercent is called to match   **
'** LookupValue with the Table entry.                                          **
'** 'Rank' is an optional parameter which may take any value > 0               **
'**        (default 1) and causes the function to return the 'nth' best        **
'**         match (where 'n' is defined by 'Rank' parameter)                   **
'** If the 'Rank' match percentage < NFPercent (Default 5%), #N/A is returned. **
'** IndexNum is the column number of the entry in TableArray required to be    **
'** returned, as follows:                                                      **
'** If IndexNum > 0 and the 'Rank' percentage match is >= NFPercent            **
'**                 (Default 5%) the column entry indicated by IndexNum is     **
'**                 returned.                                                  **
'** if IndexNum = 0 and the 'Rank' percentage match is >= NFPercent            **
'**                 (Default 5%) the offset row (starting at 1) is returned.   **
'**                 This value can be used directly in the 'Index' function.   **
'**                                                                            **
'** Algorithm can take one of the following values:                            **
'** Algorithm = 1:                                                             **
'**     This algorithm is best suited for matching mis-spellings.              **
'**     For each character in 'String1', a search is performed on 'String2'.   **
'**     The search is deemed successful if a character is found in 'String2'   **
'**     within 3 characters of the current position.                           **
'**     A score is kept of matching characters which is returned as a          **
'**     percentage of the total possible score.                                **
'** Algorithm = 2:                                                             **
'**     This algorithm is best suited for matching sentences, or               **
'**     'firstname lastname' compared with 'lastname firstname' combinations   **
'**     A count of matching pairs, triplets, quadruplets etc. in 'String1' and **
'**     'String2' is returned as a percentage of the total possible.           **
'** Algorithm = 3: Both Algorithms 1 and 2 are performed.                      **
'********************************************************************************
Dim r As Range

Dim strListString As String
Dim strWork As String

Dim sngMinPercent As Single
Dim sngWork As Single
Dim sngCurPercent  As Single
Dim intBestMatchPtr As Integer
Dim intRankPtr As Integer
Dim intRankPtr1 As Integer
Dim i As Integer

Dim lEndRow As Long

Dim udRankData() As RankInfo

Dim vCurValue As Variant

'--------------------------------------------------------------
'--    Validation                                            --
'--------------------------------------------------------------

LookupValue = LCase$(Application.Trim(LookupValue))

If IsMissing(NFPercent) Then
    sngMinPercent = 0.05
Else
    If (NFPercent <= 0) Or (NFPercent > 1) Then
        FuzzyVLookup = "*** 'NFPercent' must be a percentage > zero ***"
        Exit Function
    End If
    sngMinPercent = NFPercent
End If

If Rank < 1 Then
    FuzzyVLookup = "*** 'Rank' must be an integer > 0 ***"
    Exit Function
End If

ReDim udRankData(1 To Rank)

lEndRow = TableArray.Rows.Count
If VarType(TableArray.Cells(lEndRow, 1).value) = vbEmpty Then
    lEndRow = TableArray.Cells(lEndRow, 1).End(xlUp).Row
End If

'---------------
'-- Main loop --
'---------------
For Each r In Range(TableArray.Cells(1, 1), TableArray.Cells(lEndRow, 1))
    vCurValue = ""
    For i = 0 To AdditionalCols
        vCurValue = vCurValue & r.Offset(0, i).Text
    Next i
    If VarType(vCurValue) = vbString Then
        strListString = LCase$(Application.Trim(vCurValue))
        
        '------------------------------------------------
        '-- Fuzzy match strings & get percentage match --
        '------------------------------------------------
        sngCurPercent = FuzzyPercent(String1:=LookupValue, _
                                     String2:=strListString, _
                                     Algorithm:=Algorithm, _
                                     Normalised:=True)
        
        If sngCurPercent >= sngMinPercent Then
            '---------------------------
            '-- Store in ranked array --
            '---------------------------
            For intRankPtr = 1 To Rank
                If sngCurPercent > udRankData(intRankPtr).Percentage Then
                    For intRankPtr1 = Rank To intRankPtr + 1 Step -1
                        With udRankData(intRankPtr1)
                            .Offset = udRankData(intRankPtr1 - 1).Offset
                            .Percentage = udRankData(intRankPtr1 - 1).Percentage
                        End With
                    Next intRankPtr1
                    With udRankData(intRankPtr)
                        .Offset = r.Row
                        .Percentage = sngCurPercent
                    End With
                    Exit For
                End If
            Next intRankPtr
        End If
        
    End If
Next r

If udRankData(Rank).Percentage < sngMinPercent Then
    '--------------------------------------
    '-- Return '#N/A' if below NFPercent --
    '--------------------------------------
    FuzzyVLookup = CVErr(xlErrNA)
Else
    intBestMatchPtr = udRankData(Rank).Offset - TableArray.Cells(1, 1).Row + 1
    If IndexNum > 0 Then
        '-----------------------------------
        '-- Return column entry specified --
        '-----------------------------------
        FuzzyVLookup = TableArray.Cells(intBestMatchPtr, IndexNum)
    Else
        '-----------------------
        '-- Return offset row --
        '-----------------------
        FuzzyVLookup = intBestMatchPtr
    End If
End If
End Function
Function FuzzyHLookup(ByVal LookupValue As String, _
                      ByVal TableArray As Range, _
                      ByVal IndexNum As Integer, _
                      Optional NFPercent As Single = 0.05, _
                      Optional Rank As Integer = 1, _
                      Optional Algorithm As Integer = 3) As Variant
'********************************************************************************
'** Function to Fuzzy match LookupValue with entries in                        **
'** row 1 of table specified by TableArray.                                    **
'** TableArray must specify the top left cell of the range to be searched      **
'** The function stops scanning the table when an empty cell in row 1          **
'** is found.                                                                  **
'** For each entry in row 1 of the table, FuzzyPercent is called to match      **
'** LookupValue with the Table entry.                                          **
'** 'Rank' is an optional parameter which may take any value > 0               **
'**        (default 1) and causes the function to return the 'nth' best        **
'**         match (where 'n' is defined by 'Rank' parameter)                   **
'** If the 'Rank' match percentage < NFPercent (Default 5%), #N/A is returned. **
'** IndexNum is the row number of the entry in TableArray required to be       **
'** returned, as follows:                                                      **
'** If IndexNum > 0 and the 'Rank' percentage match is >= NFPercent            **
'**                 (Default 5%) the row entry indicated by IndexNum is        **
'**                 returned.                                                  **
'** if IndexNum = 0 and the 'Rank' percentage match is >= NFPercent            **
'**                 (Default 5%) the offset col (starting at 0) is returned.   **
'**                 This value can be used directly in the 'OffSet' function.  **
'**                                                                            **
'** Algorithm can take one of the following values:                            **
'** Algorithm = 1:                                                             **
'**     For each character in 'String1', a search is performed on 'String2'.   **
'**     The search is deemed successful if a character is found in 'String2'   **
'**     within 3 characters of the current position.                           **
'**     A score is kept of matching characters which is returned as a          **
'**     percentage of the total possible score.                                **
'** Algorithm = 2:                                                             **
'**     A count of matching pairs, triplets, quadruplets etc. in 'String1' and **
'**     'String2' is returned as a percentage of the total possible.           **
'** Algorithm = 3: Both Algorithms 1 and 2 are performed.                      **
'********************************************************************************
Dim r As Range

Dim strListString As String
Dim strWork As String

Dim sngMinPercent As Single
Dim sngWork As Single
Dim sngCurPercent  As Single

Dim intBestMatchPtr As Integer
Dim intPtr As Integer
Dim intRankPtr As Integer
Dim intRankPtr1 As Integer

Dim iEndCol As Integer

Dim udRankData() As RankInfo

Dim vCurValue As Variant
'--------------------------------------------------------------
'--    Validation                                            --
'--------------------------------------------------------------
LookupValue = LCase$(Application.Trim(LookupValue))

If IsMissing(NFPercent) Then
    sngMinPercent = 0.05
Else
    If (NFPercent <= 0) Or (NFPercent > 1) Then
        FuzzyHLookup = "*** 'NFPercent' must be a percentage > zero ***"
        Exit Function
    End If
    sngMinPercent = NFPercent
End If

If Rank < 1 Then
    FuzzyHLookup = "*** 'Rank' must be an integer > 0 ***"
    Exit Function
End If

ReDim udRankData(1 To Rank)
'**************************
iEndCol = TableArray.Columns.Count
If VarType(TableArray.Cells(1, iEndCol).value) = vbEmpty Then
    iEndCol = TableArray.Cells(1, iEndCol).End(xlToLeft).Column
End If

'---------------
'-- Main loop --
'---------------
For Each r In Range(TableArray.Cells(1, 1), TableArray.Cells(1, iEndCol))
    vCurValue = r.value
    If VarType(vCurValue) = vbString Then
        strListString = LCase$(Application.Trim(vCurValue))
        
        '------------------------------------------------
        '-- Fuzzy match strings & get percentage match --
        '------------------------------------------------
        sngCurPercent = FuzzyPercent(String1:=LookupValue, _
                                     String2:=strListString, _
                                     Algorithm:=Algorithm, _
                                     Normalised:=True)
        
        If sngCurPercent >= sngMinPercent Then
            '---------------------------
            '-- Store in ranked array --
            '---------------------------
            For intRankPtr = 1 To Rank
                If sngCurPercent > udRankData(intRankPtr).Percentage Then
                    For intRankPtr1 = Rank To intRankPtr + 1 Step -1
                        With udRankData(intRankPtr1)
                            .Offset = udRankData(intRankPtr1 - 1).Offset
                            .Percentage = udRankData(intRankPtr1 - 1).Percentage
                        End With
                    Next intRankPtr1
                    With udRankData(intRankPtr)
                        .Offset = r.Column
                        .Percentage = sngCurPercent
                    End With
                    Exit For
                End If
            Next intRankPtr
        End If
        
    End If
Next r

If udRankData(Rank).Percentage < sngMinPercent Then
    '--------------------------------------
    '-- Return '#N/A' if below NFPercent --
    '--------------------------------------
    FuzzyHLookup = CVErr(xlErrNA)
Else
    intBestMatchPtr = udRankData(Rank).Offset - TableArray.Cells(1, 1).Column + 1
    If IndexNum > 0 Then
        '-----------------------------------
        '-- Return row entry specified --
        '-----------------------------------
        FuzzyHLookup = TableArray.Cells(IndexNum, intBestMatchPtr)
    Else
        '-----------------------
        '-- Return offset col --
        '-----------------------
        FuzzyHLookup = intBestMatchPtr
    End If
End If
End Function