How to output Array in javascript

Javascript's Array output methods are: 1. Use the "for in" method to loop the array; 2. Use the for loop to output the array; 3. Use forEach to loop the array; 4. Use the for-of loop to output the array. .

The operating environment of this tutorial: windows7 system, javascript version 1.8.5, Dell G3 computer.

In JavaScript, you can traverse the array through a loop, and use the document.writeln() or console.log() method to output the array in the loop.

Example of output array in javascript:

1. Use the for in method to loop the output array:

<script language="javascript" type="text/javascript">
var str = "how are you today";
var arr = str.split(" ");
for(var key in arr){
 document.writeln(arr[key]);
}
</script>

2. Use the for loop to output the array:

<script language="javascript" type="text/javascript">
var str = "how are you today";
var arr = str.split(" ");
for(var i=0;i<arr.length;i++){
 document.writeln(arr[i]);
}
</script>

3. Use forEach loop to output the array:

var arr = [1, 2, 3, 4];
arr.forEach(function(val, index) {
    console.log(val, index);
});

4. Use for-of loop to output the array:

for-of is a new traversal array or array-like function in ES6 method. It appears mainly to solve the defects of the three traversal methods in ES5:

forEach cannot break or return

let arr=[3,7,9];
     for (let key of arr){
             console.log(key);
    }

JavaScript array:

Array objects are used in separate A series of values ​​is stored in a variable name.

[Recommended learning: javascript advanced tutorial]

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