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<head><meta charset="UTF-8"><title>列表</title>
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<body></body><script>function List() {this.dataStore = [];this.append = function (data) {//根据当前数组的长度插入新的数据this.dataStore[this.length()] = data;}this.length = function () {//获得数组的长度var length = this.dataStore.length;return length;}//如果找到当前的数据，就返回当前数据的下标，如果没有找到数据就返回-1this.find = function (data) {//1,获得数组的长度var length = this.length();//2,设置返回数据的下标var index = -1;//3,遍历数据for (var i = 0; i < length; i++) {if (data == this.dataStore[i]) {index = i;return index;}}return index;}this.forEach = function (call) {//1,获得数组的长度var length = this.length();//2,遍历数据for (var i = 0; i < length; i++) {call(this.dataStore[i]);}}//在before前面插入数据,如果before有数据，就插入在before前面，如果before没有数据，就把data插入到最前面的数据this.insertBefore = function (data,before) {//1，找到当前before数据的下标var index = this.find(before);var length = this.length();if(index==-1) {for (var i = length - 1; i >= 0; i--) {this.dataStore[i + 1] = this.dataStore[i]}this.dataStore[0] = data;}else {for (var i = length - 1; i >= index; i--) {this.dataStore[i + 1] = this.dataStore[i]}this.dataStore[index] = data;}}}var list = new List();list.append(1);list.append(2);list.append(0);list.append(10);list.append(9);list.insertBefore("在2之前插入数据",2);list.forEach(function (data) {console.log(data);});</script>
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