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 ...
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...
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) { ...
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++) { ...
JS Basics JS Loops/Conditionals break continue do-while loop for loop for-in loop if-else switch while loop JS String Methods JS Number Methods JS Math Functions JS Array Methods JavaScript: For LoopThis JavaScript tutorial explains how to use the for loop with syntax and examples....
You can also use for...in to loop through an array or a string by using their index values:const str = 'JavaScript Loops' for (const index in str) { console.log(`${str[index]} is at ${index} index.`) } // J is at 0 index. // a is at 1 index. // v is at 2 index...
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...