Initializing the 2D array elements in javascript
Question
I want to initialize and then print the elements of a 2D array using javascript. I wrote this code but nothing displays as output. How to output this array?
var m = 6;
var n = 3;
var mat = new Array[m][n];
for (i = 0; i < mat.length; i++) {
for (j = 0; j < mat[i].length; j++) {
mat[i][j]) = i * j;
document.writeln(mat[i][j]);
}
document.writeln("<br />");
}
3 answers
solution1
1 2016-02-11 21:16:35
As BenG pointed out, you've got an extra ) but you also aren't initializing your array correctly. Javascript doesn't allow you to declare multi-dimensional arrays like other languages. Instead, you'd have to do something more like this:
var m = 6;
var n = 3;
var mat = new Array(m);
for (var i = 0; i < m; i++) {
mat[i] = new Array(n);
}
solution2
1 ACCPTED 2016-02-11 21:18:57
<html> <body> </body> <script> var m=6; var n=3; var mat =new Array(m); for( var i=0; i < m ; i++){ mat[i] = new Array(n); for( var j=0;j< n ;j++){ mat[i][j] = i*j; document.writeln(mat[i][j]); } document.writeln("<br />"); } </script> </html>
solution3
0 2016-09-13 05:38:11
Javascript arrays are dynamic. They will grow to the size you require. You can call push() to add a new element to the array. It's also worth noting that you should avoid using the new keyword with objects and arrays. Use their literal notations [] for arrays and {} for objects. So a better solution here would be to push to the arrays as you need them.
var mat = [];
var m = 6;
var n = 3;
for (var i = 0; i < m; i++) {
// Let's add an empty array to our main array
mat.push([]);
for (var j = 0; j < n; j++) {
mat[i].push(i * j);
document.writeln(i * j);
}
document.writeln('<br />');
}
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