Question

I have a cell array resulted from a certain code as follows:

m = 

    [         0]    'GO:0008150'
    'GO:0008150'    'GO:0016740'
    'GO:0016740'    'GO:0016787'
    'GO:0016787'    'GO:0006810'
    'GO:0008150'    'GO:0006412'
    'GO:0016740'    'GO:0004672'
    'GO:0016740'    'GO:0016779'
    'GO:0016787'    'GO:0004386'
    'GO:0016787'    'GO:0003774'
    'GO:0016787'    'GO:0016298'
    'GO:0006810'    'GO:0016192'
    'GO:0006412'    'GO:0005215'
    'GO:0004672'    'GO:0030533'
    [         0]    'GO:0008150'
    [         0]    'GO:0016740'
    'GO:0008150'    'GO:0016787'
    'GO:0008150'    'GO:0006810'
    'GO:0006810'    'GO:0006412'
    [         0]    'GO:0004672'
    [         0]    'GO:0016779'
    [         0]    'GO:0004386'
    'GO:0016192'    'GO:0003774'
    [         0]    'GO:0016298'
    [         0]    'GO:0016192'
    'GO:0006810'    'GO:0005215'
    'GO:0005215'    'GO:0030533'

I need to remove the rows which contains zero (for example: row one should be deleted because we have a zero in the first column).
so how can I create an array from this array that doesn’t contain zeros?

Answer 1

You can do this in a pretty one-liner:

m(any(cellfun(@(x)x(1)==0, m),2), :) = []

Alternatively:

m(any(~cellfun(@ischar, m),2), :) = []

which is a tad faster.

If you can be certain that only the first column will ever contain a zero, use

m = m(cellfun(@ischar, m(:,1)),:)

and, finally, you can use

m = m(cellfun('isclass', m(:,1), 'char'),:)

which looks “old”, but actually has greater performance.

Testing these one thousand times on your example array, gives

Elapsed time is 1.382801 seconds.
Elapsed time is 0.138519 seconds.
Elapsed time is 0.075245 seconds.
Elapsed time is 0.014674 seconds.