// loop function demo1() { // before loop beforeLoopCode; for (initCode; conditionCode; stepChangeCode) { loopCode } postCode } // recursive function demo2() { beforeLoopCode; initCode function _m() { if (!conditionCode) { return } loopCode; stepChangeCode; _m() } _m() ...
For example, the same code above could be expressed as follows: JavaScript var i; for (i = 0; i <= 4; i++) { console.log(i); } Here, i is declared in line 1 separately. Inside the for loop's header in line 2, it's only assigned the value 0 to begin with. Now while th...
while- loops through a block of code while a specified condition is true do/while- also loops through a block of code while a specified condition is true The For Loop Theforstatement creates a loop with 3 optional expressions: for(expression 1;expression 2;expression 3) { ...
In JavaScript, the for loop is used for iterating over a block of code a certain number of times, or to iterate over the elements of an array. Here's a quick example of the for loop. You can read the rest of the tutorial for more details. Example for (let i = 0; i < 3; i...
我们开始探索一些特定的循环结构。第一个,你会经常使用到它,for 循环 - 以下为 for 循环的语法: for(initializer; exit-condition; final-expression) {//code to run} 我们有: 关键字for,后跟一些括号。 在括号内,我们有三个项目,以分号分隔: 一个初始化器 - 这通常是一个设置为一个数字的变量,它被递增...
When we run the code above, we’ll receive the following output: Output 0 1 2 3 In the above example, we initialized theforloop withlet i = 0, which begins the loop at0. We set the condition to bei < 4, meaning that as long asievaluates as less than4, the loop will continue ...
JavaScript for...of loop The syntax of thefor...ofloop is: for(elementofiterable) {// body of for...of} Here, iterable- an iterable object (array, set, strings, etc). element- items in the iterable In plain English, you can read the above code as: for every element in the iter...
for (var i = 0; i < items.length; i++, j++) { // loop code here that operates onitems[i]// and sometimes uses j to access adifferent array } 在上述例子中，i++、j++可以放在允许一个表达式置入的地方。在这种特殊的情况下，多个表达式的使用会产生副作用，因此复合表达式接不接受最后一个...
// code block to be executed } while(condition); Example The example below uses ado whileloop. The loop will always be executed at least once, even if the condition is false, because the code block is executed before the condition is tested: ...
一、嵌套 for 循环 1、嵌套 for 循环概念嵌套 for 循环 是一个 嵌套的 循环结构 , 其中一个 for 循环 位于另一个 for 循环的内部 , 分别是 外层 for 循环 和 内层 for...循环 ; 嵌套 for 循环 结构 常用于处理 二维数组 或 执行需要两个索引的任务 ; 2、嵌套 for ...