forked from antzucaro/matchr
-
Notifications
You must be signed in to change notification settings - Fork 0
/
jarowinkler.go
125 lines (103 loc) · 2.45 KB
/
jarowinkler.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
package matchr
func jaroWinklerBase(s1 string, s2 string,
longTolerance bool, winklerize bool) (distance float64) {
// index by code point, not byte
r1 := []rune(s1)
r2 := []rune(s2)
r1Length := len(r1)
r2Length := len(r2)
if r1Length == 0 || r2Length == 0 {
return
}
minLength := 0
if r1Length > r2Length {
minLength = r1Length
} else {
minLength = r2Length
}
searchRange := minLength
searchRange = (searchRange / 2) - 1
if searchRange < 0 {
searchRange = 0
}
var lowLim, hiLim, transCount, commonChars int
var i, j, k int
r1Flag := make([]bool, r1Length+1)
r2Flag := make([]bool, r2Length+1)
// find the common chars within the acceptable range
commonChars = 0
for i, _ = range r1 {
if i >= searchRange {
lowLim = i - searchRange
} else {
lowLim = 0
}
if (i + searchRange) <= (r2Length - 1) {
hiLim = i + searchRange
} else {
hiLim = r2Length - 1
}
for j := lowLim; j <= hiLim; j++ {
if !r2Flag[j] && r2[j] == r1[i] {
r2Flag[j] = true
r1Flag[i] = true
commonChars++
break
}
}
}
// if we have nothing in common at this point, nothing else can be done
if commonChars == 0 {
return
}
// otherwise we count the transpositions
k = 0
transCount = 0
for i, _ := range r1 {
if r1Flag[i] {
for j = k; j < r2Length; j++ {
if r2Flag[j] {
k = j + 1
break
}
}
if r1[i] != r2[j] {
transCount++
}
}
}
transCount /= 2
// adjust for similarities in nonmatched characters
distance = float64(commonChars)/float64(r1Length) +
float64(commonChars)/float64(r2Length) +
(float64(commonChars-transCount))/float64(commonChars)
distance /= 3.0
// give more weight to already-similar strings
if winklerize && distance > 0.7 {
// the first 4 characters in common
if minLength >= 4 {
j = 4
} else {
j = minLength
}
for i = 0; i < j && r1[i] == r2[i] && NaN(r1[i]); i++ {
}
if i > 0 {
distance += float64(i) * 0.1 * (1.0 - distance)
}
if longTolerance && (minLength > 4) && (commonChars > i+1) &&
(2*commonChars >= minLength+i) {
if NaN(r1[0]) {
distance += (1.0 - distance) * (float64(commonChars-i-1) /
(float64(r1Length) + float64(r2Length) - float64(i*2) + 2))
}
}
}
return
}
func Jaro(r1 string, r2 string) (distance float64) {
return jaroWinklerBase(r1, r2, false, false)
}
func JaroWinkler(r1 string, r2 string, longTolerance bool) (distance float64) {
return jaroWinklerBase(r1, r2, longTolerance, true)
}