How do I find non-zero values + lonely zeros in an array?

Hey, I would like to find the non-zero cells plus the zeros that has no zeros before or after them. For example in the array [0 1 2 2 2 0 0 4 5 0 3 0 0 0 5] I'll get the indexes: 1,2,3,4,5,8,9,10,11,15.

Thanks!

[Image Analyst]

Explain how [0 1 2 2 2 0 0 4 5 0 3 0 0 0 5] gives indexes: 1,2,3,4,5,8,9,10,11,15.

At index 1, there is a 0, but at index 2 there is a non-zero.

Explain exactly what "plus" means in "find the non-zero cells plus the zeros " Does plus mean plus, like in "+" as in addition? Or does it mean like "also" or a logical AND?

I could see if you just wanted a list of non-zero values, like find(v~=0), but you are not giving that as your desired output.

You give 2 as one of the indexes, yet the 1 at index 2 has a zero before it and you specifically said "has no zeros before or after them" so why is 2 one of the indexes when it DOES have a zero before it (at index 1)???

Answer 1

[Guillaume]

v = [0 1 2 2 2 0 0 4 5 0 3 0 0 0 5];
union(strfind([false, v == 0, false], [0 1 0]), find(v))

[Ran Cohen]

Thank you. and if I want to add another condition? for example the numbers should be bigger than x?

[Ran Cohen]

someone?

[Guillaume]

Not sure if the 0s should be included since it's not going to be greater than positive x but in any case, finding numbers greater than a value is trivial:

find(v > x)

You can put that instead of the find(v) in the above expression if you also want the 0s after a non-zero.

Answer 2

[Image Analyst]

Try this:

v = [0 1 2 2 2 0 0 4 5 0 3 0 0 0 5];
x = 2 % Threshold.
% Find v > x
% Find locations where v > x.
moreThanX = v > x
% Find zeros of length exactly 1 (is that what defines a "lonely" zero?????)
% First find location of all zeros:
allZeros = v == 0
% Now get only the regions with area = 1;
singleZeros = allZeros & ~bwareaopen(allZeros, 2)
% Combine that single zeros mask with the v>x mask to get all locations.
overallMask = singleZeros | moreThanX
% Turn logical vector into actual indexes.
out = find(overallMask)