Return logical for rows of non-zero numbers for specified columns (similar to "all" function)

Hi. I need to calculate a logical from a 1x3 matrix (although the number of columns is irrelevant) that tells me if non-zero numbers are in specified columns.

For example, if I have the following matrix callled mat:

4 16 2

6 7 7

1 4 8

0 5 19

3 0 5

9 0 16

x = all(mat,2)

x here would return a logical array where each row equaling "1" will have ALL non-zero numbers. In mat, this would only be the first 3 rows, and thus x = [1 1 1 0 0 0];

My question is whether there is an easy line of code or existing function that would allow me to specifiy which columns I would like to be non-zero in order for the logical to spit out a ero. For example, if I wanted all rows where columns 1 and 3 are non-zero, the logical that is returned should be something like this: x = [0 0 0 0 1 1] since only the last two rows fit that criteria.

Or if I wanted all rows where columns 2 and 3 were non-zero, it should return x = [0 0 0 1 0 0]

Thanks in advance!

[Matt J]

For example, if I wanted all rows where columns 1 and 3 are non-zero, the logical that is returned should be something like this: x = [0 0 0 0 1 1] since only the last two rows fit that criteria.

Why don't the first 3 rows fit the criteria? Shouldn't the result be x = [1,1,1 0 1 1]

Answer 1

[Matt J]

For example, if I wanted all rows where columns 1 and 3 are non-zero

This would be,

all(mat(:,[1,3]),2)

[BobbyRoberts]

Ah yes. Thank you. But I was hoping to have the ones where they had all 3 excluded. But I can use this and just subtract the ones that have the 2nd column.

[BobbyRoberts]

Like so:

all(mat(:,[1,3]),2) - all(mat(:,2),2)

[Matt J]

Better to do,

all(mat(:,[1,3]),2) & ~all(mat,2)