add KStr.Levenshtein

string.go

@@ -1762,3 +1762,44 @@ func (ks *LkkString) DBC2SBC(s string) string {
 func (ks *LkkString) SBC2DBC(s string) string {
 	return width.Narrow.String(s)
 }
+
+// Levenshtein 计算两个字符串之间的编辑距离,返回值越小字符串越相似.
+// 注意字符串最大长度为255.
+func (ks *LkkString) Levenshtein(a, b string) int {
+	la := len(a)
+	lb := len(b)
+
+	if a == b {
+		return 0
+	} else if la > 255 || lb > 255 {
+		return -1
+	}
+
+	d := make([]int, la+1)
+	var lastdiag, olddiag, temp int
+	for i := 1; i <= la; i++ {
+		d[i] = i
+	}
+	for i := 1; i <= lb; i++ {
+		d[0] = i
+		lastdiag = i - 1
+		for j := 1; j <= la; j++ {
+			olddiag = d[j]
+			min := d[j] + 1
+			if (d[j-1] + 1) < min {
+				min = d[j-1] + 1
+			}
+			if (a)[j-1] == (b)[i-1] {
+				temp = 0
+			} else {
+				temp = 1
+			}
+			if (lastdiag + temp) < min {
+				min = lastdiag + temp
+			}
+			d[j] = min
+			lastdiag = olddiag
+		}
+	}
+	return d[la]
+}

string_test.go

@@ -2866,3 +2866,26 @@ func BenchmarkString_SBC2DBC(b *testing.B) {
 		KStr.SBC2DBC(helloWidth)
 	}
 }
+
+func TestString_Levenshtein(t *testing.T) {
+	var res int
+
+	res = KStr.Levenshtein(helloEng, strHello)
+	assert.Greater(t, res, 0)
+
+	res = KStr.Levenshtein(helloEng, helloEngICase)
+	assert.Greater(t, res, 0)
+
+	res = KStr.Levenshtein(strHello, strHello)
+	assert.Equal(t, res, 0)
+
+	res = KStr.Levenshtein(strHello, tesHtmlDoc)
+	assert.Equal(t, res, -1)
+}
+
+func BenchmarkString_Levenshtein(b *testing.B) {
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		KStr.Levenshtein(helloEng, helloEngICase)
+	}
+}

testdata.go

@@ -172,6 +172,9 @@ var tesStr35 = "Hi jac. $a=3*5, (can you hear me?)"
 var tesStr36 = "A 'quote' is <b>bold</b>"
 var tesStr37 = "A &#39;quote&#39; is &lt;b&gt;bold&lt;/b&gt;"
 var tesStr38 = "The quick brown fox jumped over the lazy dog"
+var tesStr39 = "中国"
+var tesStr40 = "中华人民共和国"
+var tesStr41 = "中华"
 
 //中文名
 var tesChineseName1 = "李四"