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Today I've heard that it's possible to create a multi - dimensional array in js using this syntax:
var a = new Array(3,3);
a[2][2] = 2;
alert(a[2][2])
However this doesn't work in opera. Am I wrong somewhere?
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To duplicate an array, just return the element in your map call. numbers = [1, 2, 3]; numbersCopy = numbers. map((x) => x); If you'd like to be a bit more mathematical, (x) => x is called identity.
Another method to copy a JavaScript array is using Array. from() , which will also make a shallow copy, as shown in this example: If an object or array contains other objects or arrays, shallow copies will work unexpectedly, because nested objects are not actually cloned.
Creating Multidimensional Arrays You can create a multidimensional array by creating a 2-D matrix first, and then extending it. For example, first define a 3-by-3 matrix as the first page in a 3-D array. Now add a second page. To do this, assign another 3-by-3 matrix to the index value 2 in the third dimension.
Yes, you are wrong somewhere. var a = new Array(3,3); means the same as var a = [3,3];. It creates an array with two members: the Number 3 and the Number 3 again.
The array constructor is one of the worst parts of the JavaScript language design. Given a single value, it determines the length of the array. Given multiple values, it uses them to initialise the array.
Always use the var a = []; syntax. It is consistent (as well as being shorter and easier to read).
There is no short-cut syntax for creating an array of arrays. You have to construct each one separately.
var a = [
[1,2,3],
[4,5,6],
[7,8,9]
];
The code you posted makes an array consisting of two integers. You're then trying to treat an integer as an array.
mv = new Array();
mv[0] = new Array();
mv[0][0] = "value1-1";
mv[0][1] = "value1-2";
mv[1] = new Array();
mv[1][0] = "value2-1";
mv[1][1] = "value2-2";
There is no way to directly instantiate a multidimensional array.
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