Change column and row

Hi, how can I change the positions of entire row and columns in a matrix [nxm]? For example, I want to change my entire 10th row and 10th column into entire 1st column and 1st row.

Thank you.

Answer 1

[Dennie]

Hello, You can swap columns and rows quite easily in matlab. For example:

given matrix :

matrix=[1 2 3 4 5;6 7 8 9 10; 11 12 13 14 15; 16 17 18 19 20];

i can swap column 1 and 2 by performing this operation:

matrix(:,[1,2])=matrix(:,[2,1]);

for row 1 and 2, a similar operation is done:

matrix([1,2],:)=matrix([2,1],:);

Please be aware of the sequence in which you perform this operation, since column 10 and row 10 have 1 variable in common, if you swap columns and rows sequentialy, you will mix up that one variable.

Another (manual) approach to retain information is to make a copy of the row and column you want to swap in another variable such as:

copy_matrix=matrix(:,:);
matrix(2,:)=copy_matrix(1,:);
matrix(1,:)=copy_matrix(2,:);

Hope this helps,

Dennie

[nur yusof]

Excellent.Thank you so much.

Answer 2

[Ilham Hardy]

There are built-in matlab functions for this..

flipud() fliplr()

[Ilham Hardy]

For example,

matrix=[1 2 3 4 5;6 7 8 9 10; 11 12 13 14 15; 16 17 18 19 20];
>> matrix
matrix =
     1     2     3     4     5
     6     7     8     9    10
    11    12    13    14    15
    16    17    18    19    20
>> flipud(matrix)
ans =
    16    17    18    19    20
    11    12    13    14    15
     6     7     8     9    10
     1     2     3     4     5
>> fliplr(flipud(matrix))
ans =
    20    19    18    17    16
    15    14    13    12    11
    10     9     8     7     6
     5     4     3     2     1

[nur yusof]

Awesome. Thank you so much.