数组去重

题目：

【JS排序】
var str = "1245242"; //这是数组

要求从出现次数多到少排序
示例结果：2:3，4:2，1:1，5:1
【2出现3次，4出现2次...】

 

答案：

// 1
var arr = [1,2,3,4,4,5,6,7,8,8,8,9,0];
function unique(arr) {
    var tmp = new Array();
    for (var i in arr) {
        if (tmp.indexOf(arr[i]) == -1) {
            tmp.push(arr[i]);
        }
    }
    return tmp;
    console.log(tmp);
}

// 2
var str = '1245242';
var array = str.split('');
var filter = [];
var result = [];
var get = function(str,tar,arr,tmp){    
    if(str.indexOf(tar)>=0){
        tmp = str.slice(str.indexOf(tar)+1);
        arr.push(tar);
        get(tmp,tar,arr,tmp);
    }
    return arr;
}
for(i in array){
    var elm = [];
    var tmp;
    var fstr = filter.join();
    if(fstr.indexOf(array[i])>=0)
        continue;
    else{
        var tmp_arr = get(str,array[i],elm,tmp);
        result.push(tmp_arr.length+':'+tmp_arr[0]);
        filter.push(array[i]);
    }
}
result.sort();
result.reverse();
for(index in result){
    var show = result[index].split(':');
    document.write(index==0?show[1]+'出现'+show[0]+'次':'，'+show[1]+'出现'+show[0]+'次');
}


// 3
Array.prototype.unique = function () {
    var newArr = [this[0]];
    for (var i = 0, len = this.length; i < len; i++) {
        var repeat = false;
        for (var j = 0, len2 = newArr.length; j < len2; j++) {
            if (this[i] == newArr[j]) {
                repeat = true;
                break;
            }
        }
        if (!repeat) {
            newArr.push(this[i]);
        }
    }
    return newArr;
};
var arr = [1,2,3,4,5,6,7,1,2,3,4];
alert(arr.unique(arr));

// 4
Array.prototype.unique2 = function(argument) {
    this.sort();
    var newArr = [this[0]];
    for (var i = 0, len2 = this.length; i < len2; i++) {
        if (this[i] !== newArr[newArr.length - 1]) {
            newArr.push(this[i]);
        }
    }
    return newArr;
};
var array2 = ['b', 'b', 'v', 'n'];
alert(array2.unique2());


// 5
Array.prototype.unique3 = function () {
    var res = [];
    var json = {};
    for (var i = 0; i < this.length; i++) {
        if (!json[this[i]]) {
            res.push(this[i]);
            json[this[i]] = 1;
        }
    }
    return res;
}
var array3 = ['b', 'b', 'v', 'n'];
alert(array3.unique3());