Taking every nth element from each column in a matrix

Hello,

I have a 10x5 matrix:

A = randi(10,10,5);

A =

     2     8     7     1     4
     9     8     8     1     7
     4     8     2     8     8
     3     3     2    10     6
     8     7     6     7     8
     1     6     5     2     3
     1     4     9     8     8
     7     1     8     2    10
     7     8     8     2     9
     6     4     1     7     1

I would like to make another matrix (B) that contains every 2nd element from each column of A, such that

B =

     9     8     8     1     7
     3     3     2    10     6
     1     6     5     2     3
     7     1     8     2    10
     6     4     1     7     1

Thank you.

Answer 1

[Geoff Hayes]

Henry - try grabbing every other row as

 B = A(2:2:end,:);

In the above we use 2:2:end to start at row two and consider every other row thereafter (with the second 2) until we reach the end of the rows. The second parameter, :, indicates that we want all column data.

Try the above and see what happens!

[Henry Hallock]

Thank you!

[Mansour Attaallah]

thank you

[Hanlin Cheng]

thank you!!

[Ade Narayana]

Thank you!! this is what I need!!

[Khyati Jain]

How do you do this if it is a complex vector?

[Geoff Hayes]

Khyati - why would it matter if the array contains complex numbers? Or is there a particular structure to your array in that the first element is the real part of number A, the second element is the complex part of number A, etc.?

[Jonathan Harding]

Amazing

[Jianming Yuan]

excellent