CODEWITHSUNDEEP
matlabmatrix
anil
anil

Reputation: 37

how to reverse the element of matrix?

I am trying to reverse the elements of the matrix such that for given matrix order of the elements get reversed. my code is as shown for the 3x3 matrix is working.

X  = [ 1 2 3 ; 4 5 6 ; 7 8 9 ];
B = [fliplr(X(3,:));fliplr(X(2,:));fliplr(X(1,:))];

input X =

 1     2     3
 4     5     6
 7     8     9

output: B =

 9     8     7
 6     5     4
 3     2     1

the above code I am trying to generalize for any matrix with the following code 

[a,b]=size(X);
for i=0:a-1
    A  = [fliplr(X(a-i,:))];
end

but get only last row as output.

output A =

 3     2     1

please help me to concatenate all the rows of the matrix one above to each other after it got reversed.

Upvotes: 0

Views: 676

Answers (2)

Cris Luengo
Cris Luengo

Reputation: 60504

Your code doesn't work because you overwrite A in every loop iteration. Instead, you should index into A to save each of your rows.

However, fliplr can flip a whole matrix. You want to flip left/right and up/down:

B = flipud(fliplr(X));

This is the same as rotating the matrix (as Sardar posted while I was writing this):

B = rot90(X,2);

A totally different approach would work for arrays of any dimensionality:

X(:) = flipud(X(:));

Upvotes: 2

Sardar Usama
Sardar Usama

Reputation: 19689

rot90 is the function made for this purpose.

B = rot90(A,2);

Upvotes: 3

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