Find the Area under a curve for specified values (Limits)

I have a vector containing n rows (dependent on user input who gives the start and end time) and 6 columns. The first column is the time every minute and the 6th being the power at each time. I want to find the power from 08:00 to 17:00 everyday for the time defined by the user. Picture below shows this. In order to do so i found the required hours using the code shown below

DayArr = StartDateVec:minutes(1):EndDateVec;

hr = hour(DayArr);

idx(:,1) = hr>=8 & hr<17;

for the whole time period and found the rows for which i need to to extract the power values. I then chucked these required power values into another variable containing 0 for the power between 17:00 to 8:00 and the actual power values from 8:00 to 17:00 as shown below using the code

Timetable.power.*(idx(:,1))

I just need to now find the area of the power curve between these 0 values. Cumtrapz doesn't work because when the power equals 0 the value still remains the same. Any help on how I can find the cumalative power from 8-17:00 and for the remaining time the value should be 0.

I have attached the workspace for you to work with.

[Adam Danz]

Duplicate question

https://www.mathworks.com/matlabcentral/answers/1576448