for(let[key, value]ofObject.entries(obj)){ // console.log(key, value); } letendTime = performance.now(); console.log((endTime - startTime) +"ms"); } functiondoObjForLoop4(obj){ letstartTime = performance.now(); Object.entries(obj).forEach((value, key) =>{ // console.log(k...
The For/In LoopThe JavaScript for/in statement loops through the properties of an object:Example var person = {fname:"John", lname:"Doe", age:25}; var text = "";var x;for (x in person) { text += person[x]; } Try it yourself » The While Loop...
Loops can behave differently when objects have chained prototype objects. Let's see the difference we get when we use the for-in loop on an object without a prototype, as opposed to an object with a prototype object. Let's say you have an object: const obj ={ firstName:"Bar", lastNa...
Object.keys(obj).forEach((key) =>console.log(obj[key])); 另外,如果你不需要使用Object.values()来访问属性,你可以用forEach来直接循环属性的值: Object.values(obj).forEach((value) =>console.log(value)); 注意,Object.values()返回项的顺序与for...in相同。 总结 通过使用JavaScriptfor...in循环,...
Java Tutorial- For Each Loop in JavaJava Tutorial- For Each Loop in Java 1293 -- 9:50 App JavaScript专项16:JS里的switch语句,你肯定也踩过这个坑 227 -- 12:02 App C++你可能不知道的这一招第1集for loop for循环 4.8万 87 2:47 App 2分钟了解 JavaScript Event Loop | 面试必备 969 --...
forLoop, forOf, forIn, forEach, Object.entries, 已经 2019 年了, 我到底该用哪个? 看历史 从年代上讲, for Loop, 97 年就有了, ECMAScript 1st Edition (ECMA-262) for (var i = 0; i < 9; i++) { str = str + i; } for...in, 也是97 年的 var string1 = ""; var object1...
for-in-loop-diagram.png 在对象中使用for…in循环 在JavaScript中使用for...in循环迭代对象时,其迭代的键或者属性是对象自己的属性(在上面的示例中,由key变量表示)。 由于对象可能通过原型链继承数据项,其中包括对象的默认方法和属性,以及我们可能定义的对象原型,因此我们应该使用hasOwnProperty。
The For In Loop The JavaScriptfor instatement loops through the properties of an Object: Syntax for(keyinobject) { //code block to be executed } Example constperson = {fname:"John", lname:"Doe", age:25}; lettext =""; for(letxinperson) { ...
尽管for循环通常与数组一起使用,但它们也可以用来遍历JavaScript对象的属性。这需要配合使用Object.keys()或Object.entries(),将对象的键或键值对转换为数组形式,之后再遍历。 四、FOR循环与其他循环的比较 JavaScript支持多种类型的循环,包括while循环和do-while循环。这些循环各有其特点和最适用的场景: ...
JavaScript supports different kinds of loops: for- loops through a block of code a number of times for/in- loops through the properties of an object for/of- loops through the values of an iterable object while- loops through a block of code while a specified condition is true ...