calculate values for certain indexes
3 次查看(过去 30 天)
显示 更早的评论
Hello,
I have a set of data and I would like to find the total time of the data only when the set number changes. The data is shown in the picture below with the calculated time. What I'm trying to do is calculate the total time when the set# increases, if it doesnt then keep the total time same as the previous value. This is what I have so far but it's not working correctly.
lastset = 1;
timeholder = 0;
inittime = time(1);
for i = 1:length(set)
if set(i)>lastset
totaltime(i) = time(i)+timeholder;
timeholder = time(i);
lastset=set(i);
else
totaltime(i) = time(i-1);
end
end
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/148912/image.png)
0 个评论
回答(2 个)
Max Bernstein
2015-9-10
编辑:Max Bernstein
2015-9-10
1 个评论
Stephen23
2015-9-11
Please comment on your question rather than using an Answer. The Answers are for answering the question, while the comments are for commenting on it.
Image Analyst
2015-9-13
I believe this does exactly what you want. It's even vectorized as a bonus!
% Create data
setNumber = [1,1,2,2,3,3,1,1,2,2,1,1,3,3]'
theTime = [1,1.1,2,2.1,3,3.1,4,4.1,5,5.1,6,6.1,7,7.1]'
% Find out which rows we need to ignore when computing total times.
timesToIgnore = [setNumber(1); diff(setNumber)] == 0
% Zero out times for those rows.
newTimes = theTime; % Initialize copy so we don't disturb the original data.
newTimes(timesToIgnore) = 0;
% Compute total times with times of same set zeroed out.
totalTime = cumsum(newTimes)
By the way, don't use time or set or any other built-in function names as variable names.
0 个评论
另请参阅
类别
在 Help Center 和 File Exchange 中查找有关 Dates and Time 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!