How to extract a row from a transpose of a matrix

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Say I do have a matrix M=[1 2; 3 4; 5 6]
And say that I want to extract the first row from the transpose of the M matrix
Without saving the transpose of M as another matrix like doing like M_trans = M' and k = M_trans(1,:)
How to do it in a one line??
M'(1,:) won't work

Answers (1)

Cedric Wannaz
Cedric Wannaz on 26 Sep 2017
Take the first column of the original matrix.
Jan on 26 Sep 2017
Edited: Jan on 26 Sep 2017
@Chamira: Cedric is right: You cannot get the transpose on the fly by telling Matlab magically, that you do not want to create the transposed explicitly, to extract a subvector. There are 2 ways only:
  1. Create the transposed explicitly: MT = M'; k = MT(1,:)
  2. Create your own algorithm, which extract directly, what you need: k = M(:,1).'.
The work must be accomplished anywhere: Either in Matlab by calculating the complete transposed matrix, although only a part is needed, or inside your brain, such that the indirection over the transposition is omitted. But there is no smart way to let Matlab perform the task of thinking.

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