JS高效关键字搜索转

原文地址: http://www.cnblogs.com/index-html/archive/2013/04/17/js_keyword_match.html

重点关注评论中的代码..

var treeSearch = { 
    makeTree: function(strKeys) { 
        "use strict"; 
        var tblCur = {}, 
            tblRoot, 
            key, 
            str_key, 
            Length, 
            j, 
            i 
            ; 
        tblRoot = tblCur; 
        for ( j = strKeys.length - 1; j >= 0; j -= 1) { 
            str_key = strKeys[j]; 
            Length = str_key.length; 
            for ( i = 0; i < Length; i += 1) { 
                key = str_key.charAt(i); 
                if (tblCur.hasOwnProperty(key)) { //生成子节点  
                    tblCur = tblCur[key]; 
                } else { 
                    tblCur = tblCur[key] = {}; 
                } 
            } 
            tblCur.end = true; //最后一个关键字没有分割符 
            tblCur = tblRoot; 
        } 
        return tblRoot; 
    }, 
    search: function(content, tblRoot) { 
        "use strict"; 
        var tblCur, 
            p_star = 0, 
            n = content.length, 
            p_end, 
            match,  //是否找到匹配 
            match_key, 
            match_str, 
            arrMatch = [],  //存储结果 
            arrLength = 0   //arrMatch的长度索引 
            ; 
  
        while (p_star < n) { 
            tblCur = tblRoot; //回溯至根部 
            p_end = p_star; 
            match_str = ""; 
            match = false; 
            do { 
                match_key = content.charAt(p_end); 
                if (!(tblCur = tblCur[match_key])) { //本次匹配结束 
                    p_star += 1; 
                    break; 
                }else{ 
                    match_str += match_key; 
                } 
                p_end += 1; 
                if (tblCur.end === true) //是否匹配到尾部  //找到匹配关键字 
                { 
                    match = true; 
                } 
            } while (true); 
  
            if (match === true) { //最大匹配 
                arrMatch[arrLength] = { //增强可读性 
                    key: match_str, 
                    begin: p_star - 1, 
                    end: p_end 
                }; 
                arrLength += 1; 
                p_star = p_end; 
            } 
        } 
        return arrMatch; 
    } 
};

使用实例：

function test(strContent, strKeys) { 
    var arrMatch, 
        tblRoot = treeSearch.makeTree(strKeys), 
        t = new Date(); 
  
  
    arrMatch = treeSearch.search(strContent, tblRoot); 
  
    console.log("time is: " + (new Date() - t) + "mm"); 
  
    console.log(arrMatch); 
} 
var s = (function() { 
    var Things = [' ', '\n', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']; 
    var s = ""; 
    for (var i = 1000000; i >= 0; i--) { 
        s += Things[parseInt(Math.random() * Things.length) % Things.length] 
    }; 
    return s; 
})() 
test(s, ["abc", "efge", "fun", "tree"]);

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原文地址：https://www.cnblogs.com/ry123/p/3039720.html