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 ...
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-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 ...
We can useforloops to modify anarray. In the next example, we’ll create an empty array and populate it with the loop counter variable. modifyArray.js // Initialize empty arrayletarrayExample=[];// Initialize loop to run 3 timesfor(leti=0;i<3;i++){// Update array with variable val...
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...
In this for loop example, the counter variable is declared before the for loop statement as specified by: var counter; Decrement the counter variable in the for loop Traditionally, most for loops have an incrementing counter, but you can also decrement the counter. Let's look at an example...
$ node for_of2.js [ 1, 'garnet' ] [ 2, 'topaz' ] [ 3, 'opal' ] [ 4, 'amethyst' ] --- 1: garnet 2: topaz 3: opal 4: amethyst Source JS forEach In this article we have used foreach loops to go over elements of iterables in JavaScript. We have utilized theforEachmetho...
One way to putforloops in good use would be to optimize them, by removing the expressions.Each one of them can be omitted, or you can even omit them all. We will be using the same code of the example above, only we’ll modify it according to the thing we want to show you, so ...
Loops can execute a block of code a number of times.JavaScript LoopsLoops are handy, if you want to run the same code over and over again, each time with a different value.Often this is the case when working with arrays:Instead of writing: text += cars[0] + ""; text += cars[...