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- //操作字典
- var dic = new Array();//通过申明一个Array来做一个字典
- 字典中项的遍历
- for (var key in dic) {
- console.log(key + ":" + dic[key]);
- }
- //下面两种方式都可以进行删除
- delete dic["r"];
- delete dic.w;
- //操作数组
- var arr = ['a','b','c','d']
- //添加
- arr.push('q')
- //移除数组的第一个元素
- var arr = ['a','b','c','d']
- array2=arr.shift() // 'a'
- console.log(arr) ['b','c','d']
- //删除数组中的某个元素 splice
- let arr = ['a','b','c','d']
- arr.splice('b',1); //不对,不可以用内容来指定
- arr.splice(1,1); //这个输出的是["b"]
- console.log(arr)//这个输出来是["a","c","d"]
- arr.slice(1,3)//['b','c']slice是返回指定位置的元素,注意区分,这个不会改变原数组
- //数组遍历
- let arr = ['a','b','c','d']
- //$.each()遍历
- $.each(arr, function(key, value){
- console.log(key+'...'+value)
- })
- //for遍历
- for(let i = 0; i < arr.length; i++){
- console.log(arr[i])
- }
- //数组筛选,注意参数的数组和$.each()正好相反
- //找个简单的例子:
- $.grep( [0,1,2], function(n,i){
- return n > 0;
- });//返回的结果是[1,2]
- 接下来比较数组筛选的几种不同方法
- var nums = '1,2,3,4,5,jQuery,CSS,5'.split(',');
- //$.grep()
- nums = $.grep(nums, function (value, key) {
- // value = 数组元素的当前值
- // key = 当前值的下标
- return isNaN(value);
- });
- console.log(nums); //结果为: ["jQuery", "CSS"]
- //$.map()
- nums = $.map(nums, function (value, index) {
- //和$.grep() 的区别
- //return isNaN,得到结果为:[true, true]
- return isNaN(value) ? value : null;
- });
- console.log(nums); // ["jQuery", "CSS"]
- //数组合并
- var arr = ['a','b','c','d']
- var arr2 = ['d','e','f','g']
- let mergeArr = $.merge(arr,arr2 ) //['a','b','c','d','d','e','f','g']
- //连接
- var a=[1,2,3];
- var b=['a','b','c'];
- var c=["x","y","z"];
- var js=a.concat(b,c);
- console.log(js)//Array [ 1, 2, 3, "a", "b", "c", "x", "y", "z" ]
- console.log(js.join("|"))// 1|2|3|a|b|c|x|y|z
- //数组去重
- //直接对数组去重
- let yearArr = [2009,2009,2010,2010,2009,2010]
- $.unique(yearArr) // [2009,2010,2009,1010]
- //数组排序后去重
- let yearArr = [2009,2009,2010,2010,2009,2010]
- yearArr.sort()
- $.unique(yearArr) //[2009,2010]
- let yearArr = [2009,2009,2010,2010,2009,2010];
- Array.from(new Set(yearArr)) //[2009,2010]
- yearArr = [2009,2009,2010,2010,2009,2010];
- console.log(unique2(yearArr))
- function unique2(arr) {
- var ret = [];
- arr.forEach(function(item){
- if(!ret.includes(item)){
- ret.push(item);
- }
- });
- return ret;
- }
- //查找数组中元素的位置,从0开始
- var arr = [ 4, "Pete", 8, "John" ];
- $.inArray("John", arr); //3
- $.inArray(4, arr); //0
- $.inArray("David", arr); //-1
- //颠倒数组中的元素
- var a=["xhtml","css","javascript"];
- var b=a.reverse();
- console.log(a);//Array [ "javascript", "css", "xhtml" ]
- console.log(b);//Array [ "javascript", "css", "xhtml" ]
- //返回指定位置的数组 slice
- let arr = ['a','b','c','d']
- let b = arr.slice(1,3)
- console.log(arr)//Array [ "a" ,"b","c","d"]
- console.log(b)//Array [ "b", "c" ]从下标为1开始,到3结束,不包括3的位置
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