Summary of methods for traversing arrays in JavaScript

I believe everyone knows the role of arrays. It manages the storage space of multiple data in batches. Arrays have a long data structure, which can greatly improve the execution efficiency of programs, whether in PHP or ## In #JavaScript or in jQuery, the form of arrays is divided into index arrays and associative arrays, so how to traverse the array! Below we will give you a detailed introduction toJavaScript arrayTraversal~

1.for(){}Traversing the array

2.for in loop traverses the array

3.forEach methodNote: the forEach() method is introduced by the ES5.1 standard.

var arr=[1,2,3,4,5,6];
arr.forEach(function(v,i){//v==value　为arr项，i==index　为arr索引
    console.log(i+'  'v );
})//输出0  11  22  33  44  55  6

4. A new method has been added in the latest ES6 standard==for of==

for of method　 You can use subscript loops when traversing Array, but you cannot use subscripts when traversing Map and Set. Map, set – no subscript, cannot use index to traverse
In order to unify collection types, the ES6 standard introduces a new iterable type,
Array, Map and Set all belong to iterable types.
==Collections with iterable types can be traversed through the new for ... of loop. ==

var arr=[1,2,3,4,5,6];for(var value of Arr){
    console.log(value);
}  //输出123456

Summary:

The JavaScript method of traversing arrays has been summarized. Do you believe that you are familiar with arrays? We have a certain understanding of traversal , but in our actual development, we still need to choose according to our own needs, because the execution efficiency of some methods is not the best! So use with caution!

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