Jaro-Winkler String Comparison
I think this is the first Jaro-Winkler Algorithm here on PSC.
Description:
The Jaro?óÔé¼ÔÇ£Winkler distance (Winkler, 1990) is a measure of similarity between two strings. It is a variant of the Jaro distance metric (Jaro, 1989, 1995) and mainly used in the area of record linkage (duplicate detection). The higher the Jaro?óÔé¼ÔÇ£Winkler distance for two strings is, the more similar the strings are. The Jaro?óÔé¼ÔÇ£Winkler distance metric is designed and best suited for short strings such as person names. The score is normalized such that 0 equates to no similarity and 1 is an exact match.
References:
http://en.wikipedia.org/wiki/Jaro%E2%80%93Winkler_distance
lingpipe
http://lingpipe-blog.com/2006/12/13/code-spelunking-jaro-winkler-string-comparison/
Original Author: Ernanie F. Gregorio Jr.
Code
Public Function JaroWrinkler(ByVal prmKeyword As String, prmCompareTo As String) As Double
Dim iProximity As Integer ' set the number of adjacent characters to compare to
Dim i As Integer
Dim x As Integer
Dim iFrom As Integer
Dim iTo As Integer
Dim iMatchCharacters As Integer
Dim iTransposeCount As Integer
Dim iJaro As Double
prmCompareTo = UCase$(Trim$(prmCompareTo))
prmKeyword = UCase$(Trim$(prmKeyword))
If prmCompareTo <> prmKeyword Then ' check if the two words are the same
If InStr(1, prmCompareTo, prmKeyword) <= 0 Then
' compute for the proximity of character checking
' allows matching characters to be up to X number of characters away.
If Len(prmCompareTo) >= Len(prmKeyword) Then
iProximity = (Len(prmCompareTo) / 2) - 1
Else
iProximity = (Len(prmKeyword) / 2) - 1
End If
For i = 1 To Len(prmKeyword)
' this is the index of the character to be compared to
iTo = (i + iProximity) - 1
' get the left most side character based on the iProximity
If i <= iProximity Then
iFrom = 1
Else
iFrom = i - iProximity + 1
End If
' start the letter by letter comparison
For x = iFrom To iTo
If Mid$(prmKeyword, i, 1) = Mid$(prmCompareTo, x, 1) Then
If i = x Then
iMatchCharacters = iMatchCharacters + 1
GoTo exitfor
End If
iMatchCharacters = iMatchCharacters + 1
iTransposeCount = iTransposeCount + 1
Exit For
End If
Next
exitfor:
Next
iTransposeCount = iTransposeCount 2
If iMatchCharacters > 0 Then
x = 0
For i = 1 To 4
If Mid$(prmKeyword, i, 1) = Mid$(prmCompareTo, i, 1) Then
x = x + 1
Else
Exit For
End If
Next
iJaro = ((iMatchCharacters / Len(prmKeyword)) + _
(iMatchCharacters / Len(prmCompareTo)) + _
((iMatchCharacters - iTransposeCount) / iMatchCharacters)) / 3
If x > 0 Then
JaroWrinkler = iJaro + 0.1 * x * (1 - iJaro)
Else
JaroWrinkler = iJaro
End If
Else
JaroWrinkler = 0
End If
Else ' return 1 result if the keyword is within the search string
JaroWrinkler = 1
End If
Else ' return a 1 result if the string are the same
JaroWrinkler = 1
End If
End Function
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