How to extract data from an array
1 view (last 30 days)
Show older comments
Peter Darrouj
on 11 Mar 2022
Answered: Benjamin Thompson
on 11 Mar 2022
Hello. I have a signal with over 10mil data points. Whenever my signal crosses a certain threshhold i want to extract x numbers of point before and x numbers of point after it hit the threshhold.
IsEvent = true;
peakthreshhold = 120;
for i = 1:1:length(sig)
if (sig(i) >= peakthreshhold && IsEvent)
signal= (sig(i-20000):1:sig(i+50000));
disp(signal)
IsEvent = false;
end
end
so basically i wanted to extract 20000 points before it hit sig(i) to 50000 after it hit sig(i), so i get a new array with 70000 points extracted from sig(i).
If i run it now, i get 15 points
0 Comments
Accepted Answer
Benjamin Thompson
on 11 Mar 2022
Use
signal= sig(i-20000:1:i+50000);
And you probably need checks in case i < 20000 or i > (end - 50000) as special cases.
0 Comments
More Answers (1)
KSSV
on 11 Mar 2022
Let x be your signal and val be yout threshold.
val = 50000 ;
tol = 10^-3 ;
idx = find(abs(sig-val)<=tol) ; % this gives the index of your threshold
v1 = sig(1:idx) ;
v2 = sig(idx+1:end) ;
See Also
Categories
Find more on Loops and Conditional Statements in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!