How to find out if a logical array is all zeros?
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I have a logical array that is 100x1 logical. sometimes it contains a mix of numbers and sometimes it contains all 0s.
How would i go about making an if statement that checks to see if all 100x1 is 0s and if all 0s = do something
I thought i was correct in using any command but im not sure that works correctly for me..
John D'Errico on 3 Feb 2022
Edited: John D'Errico on 3 Feb 2022
any does work, with a slight tweak. But you could also use all, or sum, or nnz, or even find. There are certainly many ways.
if sum(x) == 0
if numel(find(x)) == 0
if nnz(x) == 0
Any of those tools would suffice.
More Answers (4)
Steven Lord on 3 Feb 2022
For a vector, all with one input will work.
x = ones(10, 1);
all(x > 0) % true
For a non-vector array you probably want to specify a dimension. In recent releases, you can specify a vector of dimensions on which to operate or you can specify 'all' as the dimension to operate on all the dimensions no matter how many there are.
x = ones(10, 10);
all(x > 0) % Only operate on dimension 1
all(x > 0, 'all') % Operate on dimensions 1 and 2
x = ones(10, 10, 10);
all(x > 0, [1 3]) % Operate on dimensions 1 and 3
all(x > 0, 'all') % Operate on dimensions 1, 2, and 3