自用Excel VBA函数整理 part3

'http://en.wikipedia.org/wiki/Levenshtein_distance
Public Function EditDistance(s, t, Optional costIns As Integer = 1, Optional costDel As Integer = 1, Optional costSub As Integer = 1) As Integer
'declaration, d(i,j) will hold the Levenshtein distance between
'the first i chars of s and the first j chars ot t
Static d(0 To EDIT_DISTANCE_CACHE, 0 To EDIT_DISTANCE_CACHE) As Integer

'initialization, note that (m+1)*(n+1) distances is used
m = Len(s): n = Len(t)
For x = 0 To m
For y = 0 To n
d(x, y) = 0
Next y
Next x

'source prefixes can be transformed into empty string by dropping all chars
For i = 1 To m
d(i, 0) = i * costDel
Next i
'target prefixes can be reached from empty source prefix by inserting every chars
For j = 1 To n
d(0, j) = j * costIns
Next j

For j = 1 To n
For i = 1 To m
If Mid(s, i, 1) = Mid(t, j, 1) Then
d(i, j) = d(i - 1, j - 1)
Else
d(i, j) = WorksheetFunction.Min( _
d(i - 1, j) + costDel, _
d(i, j - 1) + costIns, _
d(i - 1, j - 1) + costSub)
End If
Next i
Next j
EditDistance = d(m, n)
End Function

EditDistance

Example of workbook already enabled:
1. JSON
2. XmlHttp (via usage of API for Geocoding)
3. Geo Distance Calculation From Lng & Lat
[Download Here]