How to extract array in other arrays with for loop

JavaScript
1

Hi guys,

I’ve an array looks like this:

[
	[[0,1,2],[3,4,5],[6,7,8]],
	[[8,7,6],[5,4,3],[2,1,0]]
]

How do I get each array from the two big ones? I try a for loop but I’m unable to get them.

Thank you,

2

Here’s one way to do it:

mainArray.forEach(function (subArray) {
    subArray.forEach(function (deeperSubArray) {
        // each of the deeperSubArrays will be for example [0,1,2], or [5,4 3]
    });
});
1 Like
3

Does it have to be a for loop? Because you already have built-in methods for arrays like splice and push:

var array = [ 
  [0,1,2],[3,4,5],[6,7,8],[8,7,6],[5,4,3],[2,1,0]
]

var array1=[];
var array2=[];
var array3=[];
var array4=[];
var array5=[];
var array6=[];

  array1.push(array.slice(0,1))
  array2.push(array.slice(1,2))
  array3.push(array.slice(2,3))
  array4.push(array.slice(3,4))
  array5.push(array.slice(4,5))
  array6.push(array.slice(5,6))
  
document.write(array1 + "<br>" + array2 + "<br>" + array3 + "<br>" + array4 + "<br>" array5 + "<br>" + array6)

EDIT
This post has been reformatted by enclosing the code block in 3 backticks
```
on their own lines.

4

Thank you, it works

5

Hi v15ko,

It’s not necessary for loop. I can’t think of anything else, so I try for loop. :smile:

6

An array in Javascript has a “length” property, holding the number of its elements. For example if your array is defined as

arr = [
	[[0,1,2],[3,4,5],[6,7,8]],
	[[8,7,6],[5,4,3],[2,1,0]]
];

“arr” is a 3 dimensional array containgng 2 2-dimentional arrays inside. Let’s call each of them “row”:

Access each row using:

    for(i=0; i<arr.length; i++){
      row = arr[i]; // An array of vectors
      .
      .
      .

}
7

methods that allow you to process it without ever needing a loop.

The forEach method is the most generic but there are several others that allow you to easily perform just about any array processing with a single call instead of a loop.

Paul posted the code in post 2 of this thread that allows each of the innermost arrays to be processed directly without needing to loop over the outer two levels of array.

8

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