*!* According to this algorithm, the position of each character of the input value is to be compared with the >>>*!* position of the same characters found in the corresponding field from the file. It calculates differences >>>*!* between positions of the matching characters. >>> >>>*!* I assign a matching rate based on the difference in the number of positions. If a certain character is >>>*!* found in the same position of both the search string and the database field, I assign a matching rate of >>>*!* 100. If the two are one position away from each other, the rate is 90. Here is the complete scale: >>> >>>*!* Absolute difference between character positions Matching rate >>>*!* 0 100 >>>*!* 1 90 >>>*!* 2 80 >>>*!* 3 70 >>>*!* 4 60 >>>*!* 5 50 >>>*!* 6 40 >>>*!* 7 30 >>>*!* 8 20 >>>*!* 9 10 >>>*!* 10 or more 0 >>>LPARAMETERS tcText1, tcText2 >>> >>>m.tcText1 = ALLTRIM(m.tcText1) >>>m.tcText2 = ALLTRIM(m.tcText2) >>> >>>IF EMPTY(m.tcText1) OR EMPTY(m.tcText2) >>> RETURN 0 >>>ENDIF >>> >>>*!* force both terms to uppercase and put the shorter term in lcText1 >>>m.lcText1 = UPPER(IIF(LEN(tcText1) < LEN(tcText2), m.tcText1, m.tcText2)) >>>m.lcText2 = UPPER(IIF(LEN(tcText1) < LEN(tcText2), m.tcText2, m.tcText1)) >>> >>>LOCAL ARRAY laMatchRate[10] >>> >>>laMatchRate[1] = 100 >>>laMatchRate[2] = 90 >>>laMatchRate[3] = 80 >>>laMatchRate[4] = 70 >>>laMatchRate[5] = 60 >>>laMatchRate[6] = 50 >>>laMatchRate[7] = 40 >>>laMatchRate[8] = 30 >>>laMatchRate[9] = 20 >>>laMatchRate[10] = 10 >>> >>>*!* rather than go thru character by character if the terms match exactly >>>IF m.lcText1 == m.lcText2 >>> RETURN 100 >>>ENDIF >>> >>>m.lnrate = -1 >>>FOR i = 1 TO LEN(m.lcText1) >>> IF SUBSTR(m.lcText1, i, 1) = SUBSTR(m.lcText2, i, 1) >>> m.lnRate = m.lnRate + laMatchRate[1] >>> ELSE >>> lnPositionDiff = ABS(AT(SUBSTR(m.lcText1, i, 1), m.lcText2) - i) + 1 >>> IF BETWEEN(m.lnPositionDiff, 0, 9) >>> m.lnRate = m.lnRate + laMatchrate[m.lnPositionDiff] >>> ENDIF >>> ENDIF >>>ENDFOR >>> >>>*!* do checks from start of string and from end of string >>>FOR i = LEN(m.lcText1) TO 1 STEP -1 >>> IF SUBSTR(m.lcText1, i, 1) = SUBSTR(m.lcText2, i, 1) >>> m.lnRate = m.lnRate + laMatchRate[1] >>> ELSE >>> lnPositionDiff = ABS(AT(SUBSTR(m.lcText1, i, 1), m.lcText2) - i) + 1 >>> IF BETWEEN(m.lnPositionDiff, 0, 9) >>> m.lnRate = m.lnRate + laMatchrate[m.lnPositionDiff] >>> ENDIF >>> ENDIF >>>ENDFOR >>> >>>m.lnLengthDiff = LEN(m.lcText2) - LEN(m.lcText1) >>> >>>m.lnRank = ROUND((m.lnRate/(LEN(m.lcText1) * laMatchrate[1] * 2)) * 100, 2) - m.lnLengthDiff >>>*!* STRTOFILE(CHR(13) + TRANSFORM(m.lnrank), "Duplicate.log",1) >>>RETURN m.lnRank>>>
*!* function CalcLevenDistance >>>LPARAMETERS m.str1, m.str2 >>>LOCAL m.i, m.j, m.diagonal, m.let, m.cost, lnLengthStr1, lnLengthStr2 >>> >>>m.lnLengthStr1 = LEN(m.str1) >>>m.lnLengthStr2 = LEN(m.str2) >>> >>>DIMENSION m.arr(m.lnLengthStr1 + 1) >>>DIMENSION m.letters(m.lnLengthStr1) >>> >>>IF m.lnLengthStr1 * m.lnLengthStr2 == 0 >>> RETURN m.lnLengthStr1 + m.lnLengthStr2 >>>ENDIF >>> >>>FOR m.i = 1 TO ALEN(m.arr) >>> m.arr(m.i) = m.i >>>ENDFOR >>> >>>FOR m.i = 1 TO m.lnLengthStr1 >>> m.letters(m.i) = SUBSTR(m.str1, m.i, 1) >>>ENDFOR >>> >>>FOR m.i = 1 TO m.lnLengthStr2 >>> m.diagonal = m.arr(1) - 1 >>> m.arr(1) = m.i + 1 >>> m.let = SUBSTR(m.str2, m.i, 1) >>> FOR m.j = 1 TO m.lnLengthStr1 >>> m.cost = m.diagonal >>> IF m.letters(m.j) != m.let >>> m.cost = m.cost + 1 >>> ENDIF >>> IF m.cost > m.arr(m.j) >>> m.cost = m.arr(m.j) >>> ENDIF >>> IF m.cost > m.arr(m.j + 1) >>> m.cost = m.arr(m.j + 1) >>> ENDIF >>> m.diagonal = m.arr(m.j + 1) - 1 >>> m.arr(m.j + 1) = m.cost + 1 >>> ENDFOR >>>ENDFOR >>> >>>RETURN 100 - (m.arr(ALEN(m.arr)) - 1) >>>>>>