Number of rows for given y

Hey,

i have loaded a .mat file in my workspace which contains 9x2 double.

First column represents x-values and second column y-vaules.

I have a specific y-values and want to find the number of rows with that y-value.

How can I calculate that?

Thank you!

Answer 1

[Voss]

M = randi(10,9,2) % random 9-by-2 matrix of integers between 1 and 10

M = 9×2

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

y = 6; % y value to find in the second column of M

nnz(M(:,2) == y) % number of times y appears in the second column of M

ans = 2

[Voss]

If you want to count the number of rows of M that have y in either column:

M = randi(10,9,2)

M = 9×2

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

y = 6;

nnz(any(M == y,2))

ans = 3

[Christopher Schoß]

Thank you!! Appreciate your help!

[Voss]

You're welcome!