how to use "for" loop to save variables to an array?

I have a data vector.it has severals positive and negative areas. I have calculated each area one by one using trapz function. is there any way to find this area using loop ?

I have used this for loop, but showing only the last result.attaced the "mat" file here.

loop:

i=0;

for i=1:length(zeroaxes)

time(i:zeroaxes(i))=time(i:zeroaxes(i));

power(i:zeroaxes(i),1)=power(i:zeroaxes(i));

areaone=trapz(time,power);

end

Code(Manually calculated the area using trapz):

A=load('power.mat');

power=A.power;

time=1:length(power);

zci = @(v) find(v(:).*circshift(v(:), [-1 0]) <= 0); % Returns Zero-Crossing Indices

zeroaxes = zci(power);

%% Area Calculation

time_1=time(1:zeroaxes(2)); % time of area1 calculation

power_1=power(1:zeroaxes(2)); % power of area1

area_1=trapz(time1,power1); % integrated area1

time_2=time(zeroaxes(2):zeroaxes(3));

power_2=power(zeroaxes(2):zeroaxes(3));

area_2=trapz(time2,power2);

time_3=time(zeroaxes(3):zeroaxes(4));

power_3=power(zeroaxes(3):zeroaxes(4));

area_3=trapz(time3,power3);

time_4=time(zeroaxes(4):zeroaxes(5));

power_4=power(zeroaxes(4):zeroaxes(5));

area_4=trapz(time4,power4);

time_5=time(zeroaxes(5):zeroaxes(6));

power_5=power(zeroaxes(5):zeroaxes(6));

area_5=trapz(time5,power5);

Answer 1

[cr]

Of course, it will show the last result only since you are overwriting the areaone variable in every iteration of the loop. You might want to do

areaone(i)= trapz(time,power);

inside the loop.

[Stephen23]

Tashaf hoq's incorrectly posted "Answer" moved here:

yes, almost like that.

actually in my mat file has 15 areas. Zero-Crossing Indices(zci) has 16 elements.so my data has 15 areas.to avoid bunch of lines i have just provided the code for 5 areas. so want to calculate these 15 areas with loop. everytime doing manually/one by one is time wasting initiation.

could you please light up about the syntax ?