Find out if X out of Y elements of an array are true

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A VP 2019-5-31

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评论： A VP 2019-6-3

I have an array of 5 elements. The array is updated at any index (1,2,3,4,5) in each simulation time to a value TRUE or FALSE. In the next function, I should check if 4 out of 5 elements including the last updated element of the array are TRUE. Is there a way to check this?

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Answer 1

Jos (10584) 2019-5-31

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Let TF be your logical array and X the index of the last updated element then

ConditionIsMet = TF(x) && sum(TF) == 4

will be true if your condition is met.

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A VP 2019-6-1

This works. Thank you.

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Answer 2

Arvind Sathyanarayanan 2019-5-31

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编辑：Arvind Sathyanarayanan 2019-5-31

在 MATLAB Online 中打开

You can do something like this :

X=sum(Array(:) == 1);
if X>=4
    disp('4 or more elements are true')
end

If they are 1s and 0s, you can just count the non zero elements using the nnz() function.

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Jos (10584) 2019-6-1

Logically, when one element changes at a time, (let's say, the k-th), the condition that 4 out of 5 are ture, is met can only happen when that element has become true. So, logically, that check is not really necessary ...

A VP 2019-6-3