CODEWITHSUNDEEP
matlabmatrixoctave
Paul Lemarchand
Paul Lemarchand

Reputation: 2096

Octave access elements of matrix by lines

I made a matrix like this :

A = randi([-10, 10], 3, 3);

Which can have this result :

-1    1   -2
2    2    8
5    3   10

How can I transform it in a way that A(1) = -1, A(2) = 1 and A(3) = -2 (Accessing first line with terms 1,2,3)

Currently, A(1) = -1, A(2) = 2 and A(3) = 5 (columns)

Note : Not only the first line, but I want to access all elements sorted by lines

Thank you !

Upvotes: 0

Views: 673

Answers (1)

Sardar Usama
Sardar Usama

Reputation: 19689

In Octave and MATLAB, data is stored in column-major order which means for your matrix, indices and elements are like this:

A matrix

You need to take the transpose of the original matrix to access them the way you stated. In Octave, you can directly access them using A.'(1) , A.'(2), A.'(3) etc. In MATLAB, you cannot access them like Octave. So save them in a new matrix or replace the contents of the previous matrix. i.e. A = A.' and then you can use A(1), A(2), A(3) etc to access the desired elements.

A.' or transpose(A) for the given A actually gives:

transpose(A)

So now as per the column major order, first, second and third elements are -1, 1 and -2 respectively and so on.

Upvotes: 3

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