JavaScript经典实例

1.指定范围生成随机数

function random(min, max) {
    if (arguments.length === 2) {
        return Math.floor(min + Math.random() * ((max + 1) - min))
    } else {
        return null;
    }
}
console.log(random(10,20));

2.去重

function unique(arr){
    if (Array.hasOwnProperty('from')) {
        return Array.from(new Set(arr));
    } else {
        var n = {}, r = [];
        for (var i = 0; i < arr.length; i++) {
            if (!n[arr[i]]) {
                n[arr[i]] = true;
                r.push(arr[i]);
            }
        }
        return r;
    }
}
var arr = [1,2,3,1,2,3,4];
console.log(unique(arr));

3.获取最大值

 

function max(arr) {
    return Math.max.apply(null,arr1)
}
var arr = [1,2,3,4,1,2,3,4];
console.log(max(arr));

4.获取最小值

function min(arr) {
    return Math.min.apply(null,arr1)
}
var arr = [1,2,3,4,1,2,3,4];
console.log(min(arr));

5.判断一个元素中是否在数组中

function contains(arr,val) {
    return arr.indexOf(val) != -1 ? true : false;
}
var arr = [1,2,3,1,2,3,4];
console.log(contains(arr,1));

 6.两个数组合并

var list1 = [1,2,3,4,5];
var list2 = [7,8,9,0];
function union () {
    var newArr = list1.concat(list2);
    return newArr;
}
console.log(union());

 

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