Extracting elements of a matrix in the first row and even columns

I want to manipulate only the components of a matrix which are int the first row and even columns, so (1, 2), (1, 4), etc. To extract the even columns I used: B(:,2:2:end); and for the elements in the first row: B(1,:);

Combining the two: B(1,:,2:2:end); I would get an empty array. Is there a way to this in a single expression?

Answer 1

[Stephen23]

B(1,2:2:end)

As the documentation clearly explains, the first position is for rows, the second for columns, the third for pages, etc. Exactly like in the Mathematics that you learned at high school:

array(row,col,page,...)

This very basic MATLAB (and Maths) syntax is explained in the introductory tutorials, which are highly recommended for all beginners:

https://www.mathworks.com/help/matlab/getting-started-with-matlab.html

https://www.mathworks.com/help/matlab/math/matrix-indexing.html

https://www.mathworks.com/help/matlab/learn_matlab/array-indexing.html