我正在寻找一个可以比较两个字符串并返回它们相似的可能性的JavaScript函数。我看过soundex，但这对于多字符串或非名字来说并不是很好。我正在寻找像以下这样的功能：
function compare(strA,strB){
}
compare("Apples","apple") = Some X Percentage.
该函数适用于所有类型的字符串，包括数字，多字值和名称。也许我可以使用一个简单的算法？
Ultimately none of these served my purpose so I used this:
function compare(c, u) {
var incept = false;
var ca = c.split(",");
u = clean(u);
//ca = correct answer array (Collection of all correct answer)
//caa = a single correct answer word array (collection of words of a single correct answer)
//u = array of user answer words cleaned using custom clean function
for (var z = 0; z < ca.length; z++) {
caa = $.trim(ca[z]).split(" ");
var pc = 0;
for (var x = 0; x < caa.length; x++) {
for (var y = 0; y < u.length; y++) {
if (soundex(u[y]) != null && soundex(caa[x]) != null) {
if (soundex(u[y]) == soundex(caa[x])) {
pc = pc + 1;
}
}
else {
if (u[y].indexOf(caa[x]) > -1) {
pc = pc + 1;
}
}
}
}
if ((pc / caa.length) > 0.5) {
return true;
}
}
return false;
}
// create object listing the SOUNDEX values for each letter
// -1 indicates that the letter is not coded, but is used for coding
// 0 indicates that the letter is omitted for modern census archives
// but acts like -1 for older census archives
// 1 is for BFPV
// 2 is for CGJKQSXZ
// 3 is for DT
// 4 is for L
// 5 is for MN my home state
// 6 is for R
function makesoundex() {
this.a = -1
this.b = 1
this.c = 2
this.d = 3
this.e = -1
this.f = 1
this.g = 2
this.h = 0
this.i = -1
this.j = 2
this.k = 2
this.l = 4
this.m = 5
this.n = 5
this.o = -1
this.p = 1
this.q = 2
this.r = 6
this.s = 2
this.t = 3
this.u = -1
this.v = 1
this.w = 0
this.x = 2
this.y = -1
this.z = 2
}
var sndx = new makesoundex()
// check to see that the input is valid
function isSurname(name) {
if (name == "" || name == null) {
return false
} else {
for (var i = 0; i < name.length; i++) {
var letter = name.charAt(i)
if (!(letter >= 'a' && letter <= 'z' || letter >= 'A' && letter <= 'Z')) {
return false
}
}
}
return true
}
// Collapse out directly adjacent sounds
// 1. Assume that surname.length>=1
// 2. Assume that surname contains only lowercase letters
function collapse(surname) {
if (surname.length == 1) {
return surname
}
var right = collapse(surname.substring(1, surname.length))
if (sndx[surname.charAt(0)] == sndx[right.charAt(0)]) {
return surname.charAt(0) + right.substring(1, right.length)
}
return surname.charAt(0) + right
}
// Collapse out directly adjacent sounds using the new National Archives method
// 1. Assume that surname.length>=1
// 2. Assume that surname contains only lowercase letters
// 3. H and W are completely ignored
function omit(surname) {
if (surname.length == 1) {
return surname
}
var right = omit(surname.substring(1, surname.length))
if (!sndx[right.charAt(0)]) {
return surname.charAt(0) + right.substring(1, right.length)
}
return surname.charAt(0) + right
}
// Output the coded sequence
function output_sequence(seq) {
var output = seq.charAt(0).toUpperCase() // Retain first letter
output += "-" // Separate letter with a dash
var stage2 = seq.substring(1, seq.length)
var count = 0
for (var i = 0; i < stage2.length && count < 3; i++) {
if (sndx[stage2.charAt(i)] > 0) {
output += sndx[stage2.charAt(i)]
count++
}
}
for (; count < 3; count++) {
output += "0"
}
return output
}
// Compute the SOUNDEX code for the surname
function soundex(value) {
if (!isSurname(value)) {
return null
}
var stage1 = collapse(value.toLowerCase())
//form.result.value=output_sequence(stage1);
var stage1 = omit(value.toLowerCase())
var stage2 = collapse(stage1)
return output_sequence(stage2);
}
function clean(u) {
var u = u.replace(/\,/g, "");
u = u.toLowerCase().split(" ");
var cw = ["ARRAY OF WORDS TO BE EXCLUDED FROM COMPARISON"];
var n = [];
for (var y = 0; y < u.length; y++) {
var test = false;
for (var z = 0; z < cw.length; z++) {
if (u[y] != "" && u[y] != cw[z]) {
test = true;
break;
}
}
if (test) {
//Don't use & or $ in comparison
var val = u[y].replace("$", "").replace("&", "");
n.push(val);
}
}
return n;
}
答案 0 :(得分：90)
这是基于Levenshtein距离https://en.wikipedia.org/wiki/Levenshtein_distance
的答案function similarity(s1, s2) {
var longer = s1;
var shorter = s2;
if (s1.length < s2.length) {
longer = s2;
shorter = s1;
}
var longerLength = longer.length;
if (longerLength == 0) {
return 1.0;
}
return (longerLength - editDistance(longer, shorter)) / parseFloat(longerLength);
}
用于计算编辑距离
function editDistance(s1, s2) {
s1 = s1.toLowerCase();
s2 = s2.toLowerCase();
var costs = new Array();
for (var i = 0; i <= s1.length; i++) {
var lastValue = i;
for (var j = 0; j <= s2.length; j++) {
if (i == 0)
costs[j] = j;
else {
if (j > 0) {
var newValue = costs[j - 1];
if (s1.charAt(i - 1) != s2.charAt(j - 1))
newValue = Math.min(Math.min(newValue, lastValue),
costs[j]) + 1;
costs[j - 1] = lastValue;
lastValue = newValue;
}
}
}
if (i > 0)
costs[s2.length] = lastValue;
}
return costs[s2.length];
}
用法
similarity('Stack Overflow','Stack Ovrflw')
返回0.8571428571428571
你可以在下面玩它：
function checkSimilarity(){
var str1 = document.getElementById("lhsInput").value;
var str2 = document.getElementById("rhsInput").value;
document.getElementById("output").innerHTML = similarity(str1, str2);
}
function similarity(s1, s2) {
var longer = s1;
var shorter = s2;
if (s1.length < s2.length) {
longer = s2;
shorter = s1;
}
var longerLength = longer.length;
if (longerLength == 0) {
return 1.0;
}
return (longerLength - editDistance(longer, shorter)) / parseFloat(longerLength);
}
function editDistance(s1, s2) {
s1 = s1.toLowerCase();
s2 = s2.toLowerCase();
var costs = new Array();
for (var i = 0; i <= s1.length; i++) {
var lastValue = i;
for (var j = 0; j <= s2.length; j++) {
if (i == 0)
costs[j] = j;
else {
if (j > 0) {
var newValue = costs[j - 1];
if (s1.charAt(i - 1) != s2.charAt(j - 1))
newValue = Math.min(Math.min(newValue, lastValue),
costs[j]) + 1;
costs[j - 1] = lastValue;
lastValue = newValue;
}
}
}
if (i > 0)
costs[s2.length] = lastValue;
}
return costs[s2.length];
}<div><label for="lhsInput">String 1:</label> <input type="text" id="lhsInput" oninput="checkSimilarity()" /></div>
<div><label for="rhsInput">String 2:</label> <input type="text" id="rhsInput" oninput="checkSimilarity()" /></div>
<div>Match: <span id="output">No Input</span></div>
答案 1 :(得分：15)
这是一个非常简单的函数，它进行比较并根据等效性返回百分比。虽然尚未针对所有可能的情况进行测试，但它可能有助于您入门。
function similar(a,b) {
var lengthA = a.length;
var lengthB = b.length;
var equivalency = 0;
var minLength = (a.length > b.length) ? b.length : a.length;
var maxLength = (a.length < b.length) ? b.length : a.length;
for(var i = 0; i < minLength; i++) {
if(a[i] == b[i]) {
equivalency++;
}
}
var weight = equivalency / maxLength;
return (weight * 100) + "%";
}
alert(similar("test","tes")); // 75%
alert(similar("test","test")); // 100%
alert(similar("test","testt")); // 80%
alert(similar("test","tess")); // 75%
答案 2 :(得分：6)
来自PHP.js library的功能similar_text怎么样？
它基于带有the same name的PHP函数。
function similar_text (first, second) {
// Calculates the similarity between two strings
// discuss at: http://phpjs.org/functions/similar_text
if (first === null || second === null || typeof first === 'undefined' || typeof second === 'undefined') {
return 0;
}
first += '';
second += '';
var pos1 = 0,
pos2 = 0,
max = 0,
firstLength = first.length,
secondLength = second.length,
p, q, l, sum;
max = 0;
for (p = 0; p < firstLength; p++) {
for (q = 0; q < secondLength; q++) {
for (l = 0;
(p + l < firstLength) && (q + l < secondLength) && (first.charAt(p + l) === second.charAt(q + l)); l++);
if (l > max) {
max = l;
pos1 = p;
pos2 = q;
}
}
}
sum = max;
if (sum) {
if (pos1 && pos2) {
sum += this.similar_text(first.substr(0, pos2), second.substr(0, pos2));
}
if ((pos1 + max < firstLength) && (pos2 + max < secondLength)) {
sum += this.similar_text(first.substr(pos1 + max, firstLength - pos1 - max), second.substr(pos2 + max, secondLength - pos2 - max));
}
}
return sum;
}
答案 3 :(得分：6)
我很快就写了一篇可能适合你的目的：
function Compare(strA,strB){
for(var result = 0, i = strA.length; i--;){
if(typeof strB[i] == 'undefined' || strA[i] == strB[i]);
else if(strA[i].toLowerCase() == strB[i].toLowerCase())
result++;
else
result += 4;
}
return 1 - (result + 4*Math.abs(strA.length - strB.length))/(2*(strA.length+strB.length));
}
这对于相同但不同情况的字符的权重是完全不同或缺失的字符的四分之一。它返回0到1,1之间的数字，表示字符串相同。 0表示它们没有相似之处。例子：
Compare("Apple", "Apple") // 1
Compare("Apples", "Apple") // 0.8181818181818181
Compare("Apples", "apple") // 0.7727272727272727
Compare("a", "A") // 0.75
Compare("Apples", "appppp") // 0.45833333333333337
Compare("a", "b") // 0
答案 4 :(得分：2)
使用 this 库进行字符串相似性对我来说就像一个魅力！
这是示例 -
var similarity = stringSimilarity.compareTwoStrings("Apples","apple"); // => 0.88
答案 5 :(得分：1)
fuzzyset-为javascript设置的模糊字符串。 Fuzzyset是一种数据结构，对数据执行类似于全文搜索的操作，以确定可能的拼写错误和近似的字符串匹配。请注意，这是python库的javascript端口。
答案 6 :(得分：-1)
查找两个字符串之间的相似度；我们可以使用一种或两种以上的方法，但我主要倾向于使用'Dice's Coefficient'。哪个更好！据我所知，它比使用'Levenshtein distance'
使用npm中的这个'string-similarity'软件包，您将可以按照我上面所说的进行操作。
一些简单的用法示例
var stringSimilarity = require('string-similarity');
var similarity = stringSimilarity.compareTwoStrings('healed', 'sealed');
var matches = stringSimilarity.findBestMatch('healed', ['edward', 'sealed', 'theatre']);
有关更多信息，请访问上面给出的链接。谢谢。