How to select the columns of a matrix which are a multiple of 5?

1 view (last 30 days)
I don't know how to solve the following exercise:
M is a 3x5000 matrix. A student wants to select the elements on the third row in all columns which are a multiple of 5.
The student writes the following script.
N = zeros(1,1000)
for i = 1:5000
if rem(i,5) == 0
N(i/5) = M(3,i);
I have to simplify it using only N = M(...). How do I do that?
  1 Comment
Guillaume on 9 Jan 2020
It's hard to give you any help without giving the solution away (which would be cheating).
For which i values would the if be true? Couldn't you pass these values directly as indices of M and not bother with the loop?

Sign in to comment.

Answers (2)

Alex Mcaulley
Alex Mcaulley on 9 Jan 2020
N = M(3,5:5:end)

Sign in to comment.

Ellen De Jonghe
Ellen De Jonghe on 9 Jan 2020
Hi guys, thanks a lot for your help!
I managed to solve exercises which are way more difficult, but my mind is still full of my previous exam stuff, so I didn't see that the solution ofr this case was so simple. Hope that makes sense ;)


Find more on Programming in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!