Finding the length distribution of zeros in data?

39 views (last 30 days)
Pappis
Pappis on 2 Sep 2025 at 13:05
Edited: Matt J on 4 Sep 2025 at 15:44
I have a data set of several measurements, which give me the values at given time intervals (e.g. once a minute). Every now and then, the value is missed, e.g. due to a random fault, and the missing value is marked as "0" (zero).
I have experience handling the data, but got a new request to debug the faults more closely. I need to find the length distribution of these zeros, i.e. how long the faults are typically? Are they single-value misses, or longer?
So, how do I evaluate the lengths for each of these faults, and/or their length distribution? I prefer answers without the Statictical toolbox, but if needed I have access to that, too.

Accepted Answer

Stephen23
Stephen23 on 2 Sep 2025 at 13:16
Edited: Stephen23 on 2 Sep 2025 at 13:19
Fake data:
V = rand(1,123);
V(randi(123,1,23)) = 0;
V(5:7) = 0
V = 1×123
0.7107 0.4742 0.0842 0.5311 0 0 0 0.0510 0.3399 0.4221 0.8725 0.0811 0.3725 0.0362 0.9471 0.0934 0.2950 0.4100 0.0774 0.6726 0.3011 0.4228 0.9944 0.1799 0 0.5158 0.2221 0.3628 0.6641 0.0212
<mw-icon class=""></mw-icon>
<mw-icon class=""></mw-icon>
D = diff([false;V(:)==0;false]);
L = find(D<0) - find(D>0);
histogram(L)

More Answers (1)

Matt J
Matt J on 3 Sep 2025 at 12:13
Edited: Matt J on 4 Sep 2025 at 15:44
You can use this File Exchange submission,
V = rand(1,123);
V(randi(123,1,23)) = 0;
V(5:7) = 0;
[~,~,zeroLengths] = groupLims(groupTrue(~V),1);
histogram(zeroLengths)
  1 Comment
Pappis
Pappis on 4 Sep 2025 at 7:29
Moved: Rik on 4 Sep 2025 at 7:55
I like Stephen's elegant solution very much. It's also easier to understand while reading the code. Thank you for your quick reply!

Sign in to comment.

Products


Release

R2021b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!