代码语言:javascript 代码运行次数:0 运行 AI代码解释 constarr=[100,'B',4,'5',3,'A',0];for(constkeyinarr){console.log(`index:${key}value:${arr[key]}`);}console.log('___\n');functionFoo(){this[100]=100;this.B='B';this[4]=4;this['5']='5';this[3]=3;this.A='A';t...
star: 63}]想要获取name的值的数组,更适合用mapgroup.map(function(item){ return item.name})结果:// ['张三', '李四']如果想要得到star的总数,就更适合用forEachvar sum = 0group.forEach(function(item){ sum += item.star})结果:// sum 86 ...
forEach(function(element,index){ console.log(element + '/' + index); }) //输出结果: first/0 second/1 third/2 fourth/3 3/4 5/5 8/6 5.map 遍历数组,并通过callback对数组元素进行操作,并将所有操作结果放入数组中并返回该数组(不能遍历伪数组) var arr = ["first","second",'third' ...
Array.prototype.forEach = function forEach(callback) { // 获取数组长度 var len = this.length; if(typeof callback != "function") { throw new TypeError(); } // thisArg为callback 函数的执行上下文环境 var thisArg = arguments[1]; for(var i = 0; i < len; i++) { if(i in this)...
Underscore.js every Function - Learn how to use the Underscore.js 'every' function to test if all elements in a collection pass a given predicate.
这些内容在前面的章节已经讲过了,遗忘的童鞋记得温故知新呀。 find、findIndex 在编程过程中常常会遇到对象数组,而对象是不能直接使用===比较的,如何从数组中查找到满足条件的对象呢? 这个时候就要使用find和findIndex方法,语法如下: letresult=arr.find(function(itm...
In JavaScript, functions are executed in the order they are called. The call stack follows the Last In, First Out (LIFO) principle, meaning that the last function pushed onto the stack is the first one to be executed.According to the ECMAScript specification, the call stack is defined as ...
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As inexpensive as can be made and still function as a keyboard. A mechanical keyboard is different because each and every key has an individual key switch under it. It has a kind of an assembly with a spring under it. And there’s many kinds of these key switches and they vary in fee...
Array.prototype.myUnshit=function(){ varlen=this.length; varinLen=arguments.length; for(vari=len-1;i>=0;i--){ // this[0] = arguments[i] this[i+inLen]=this[i] } for(vari=0;i<inLen;i++){ this[i]=arguments[i] } returnthis.length; ...