Rotate a matrix array by 180 degrees?

Question

I have a square matrix (might be even or odd nr of items per side) and I wish to rotate it 180 degrees. That is rotate, not flip.

I have found many rotation by 90 degrees of varying shape but no luck finding one for 180 degrees. My matrix could be very large to make doing 2x 90 degree runs unacceptable.

Why are you doing this? You just asked a question and answered it yourself. — thefourtheye
– thefourtheye, Commented Oct 12, 2013 at 10:13
@thefourtheye the website permits Q&A format which I took. You didn't have to downvote everything. — Discipol
– Discipol, Commented Oct 12, 2013 at 15:43
I promise. I didnt downvote any of your posts. You can check my profile for my downvotes. — thefourtheye
– thefourtheye, Commented Oct 12, 2013 at 16:46
You have quelled my thirst of vengeance, for now, @thefourtheye; but I promise you, when I find those response, there will be paint >:) — Discipol
– Discipol, Commented Oct 12, 2013 at 17:25

Ibrahim Najjar · Accepted Answer · 2013-10-12 10:19:43Z

5

Try the following:

grid.reverse().forEach(function(item) { item.reverse(); } );
console.log(grid);

answered Oct 12, 2013 at 10:19

Ibrahim Najjar

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1 Comment

georg Over a year ago

Or, define reversed(a) as a.slice(0).reverse() and then rotated = reversed(grid).map(reversed).

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