find the index who have the max value in cell structure

i have a cell structure like this:

ex1=[1 2 3];
ex2=[2 3 0];

for i=1:3
a(i).b=struct('ex1',ex1(i),'ex2',ex2(i));
end

how can i find the index of a(i) who have the max value of ex1 but the ex2 must be greater than 0?

Answer 1

[Voss]

ex1=[1 2 3];
ex2=[0 3 2];
for i=1:3
    a(i).b = struct('ex1',ex1(i),'ex2',ex2(i));
end

temp = [a.b];
posidx = find([temp.ex2] > 0);
[maxval,tempidx] = max([temp(posidx).ex1]);
maxidx = posidx(tempidx);

disp(maxval);

     3

disp(maxidx);

     3

[ahmad]

why if the ex2 start with 0 the answer of index is not the same as the max value of ex1 anymore?

for example is i change ex2 to ex2=[0 3 2] like this

ex1=[1 2 3];
ex2=[0 3 2];
for i=1:3
    a(i).b = struct('ex1',ex1(i),'ex2',ex2(i));
end
temp = [a.b];
[maxval,maxidx] = max([temp([temp.ex2] > 0).ex1])

maxval = 3

maxidx = 2

the answer is maxval=3 and maxidx=2?

isn't the answer suppost to be maxval=3 and maxidx=3?

[Voss]

You're right. I've changed the answer and changed the ex2 to [0 3 2], and it now gives the expected result.