for-in循环应该用在非数组对象的遍历上,使用for-in进行循环也被称为“枚举”。 从技术上将,你可以使用for-in循环数组(因为JavaScript中数组也是对象),但这是不推荐的。因为如果数组对象已被自定义的功能增强,就可能发生逻辑错误。另外,在for-in中,属性列表的顺序(序列)是不能保证的。所以最好数组使用正常的for循...
do…while— loops through a block of code once; then the condition is evaluated. If the condition is true, the statement is repeated as long as the specified condition is true. for— loops through a block of code until the counter reaches a specified number. for…in— loops through the ...
for-in循环应该用在非数组对象的遍历上,使用for-in进行循环也被称为“枚举”。从技术上将,你可以使用for-in循环数组(因为JavaScript中数组也是对象),但这是不推荐的。因为如果数组对象已被自定义的功能增强,就可能发生逻辑错误。另外,在 ...
2、“for…in…”循环 为了使对象的迭代更容易,有一个“for...in...”语法,它也可以从 ES3 获得。 var author = {name: "Yang", job: "programmer"}for (var k in author){console.log(k + ':' + author[k]);}//name:Yang//job:programmer ...
javascript之for-in循环(for-in Loops) for-in循环应该用在非数组对象的遍历上,使用for-in进行循环也被称为“枚举”. 从技术上将,你可以使用for-in循环数组(因为JavaScript中数组也是对象),但这是不推荐的.因为如果数组对象已被自定义的功能增强,就可能发生逻辑错误.另外,在for-in中,属性列表的顺序(序列)是不能...
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 while - loops through a block of code while a specified condition is true do/while - also loops through a block of code while a ...
For/Of and For/In Loops Thefor/inloop and thefor/ofloop are explained in the next chapter. While Loops Thewhileloop and thedo/whileare explained in the next chapters. Exercise? Consider the following code: let i, x = ''; for (i = 0; i <= 5; i++) { ...
JavaScript Patterns 2.4 For-in loop Principle Enumeration should be used to iterate over nonarray objects. It's important to use the methodhasOwnProperty()when iterating over object properties to filter out properties that come down the prototype chain....
Why Use For Loops in JavaScript Code In JavaScript, just as in other programming languages, we use loops to read or access the items of a collection. The collection can be an array or an object. Every time the loop statement cycles through the items in a collection, we call it aniterati...
一篇文章带你了解JavaScript for循环 大家好,我是前端进阶者。我们都知道,有了循环,就可以多次执行一段代码。 一、JavaScript 循环 循环是方便的,如果你想重复地运行同一个代码,每次使用不同的值。 通常情况下,这是与数组一起工作: 复制 text += cars[0] + ""; text...