Extracting the index numbers of greater than zero values of an array in different / separate sets MATLAB
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I have an array of n length. Array has braking energy values. Index numbers represents Time in seconds.
Structure of array is as following:
1 to 140 index numbers array has zero values. (The time during which vehicle was not braking)
141 to 200 index numbers array has random energy values. (The time when vehicle was braking and regenerating energy)
201 to 325 index number array has zero values. (The time during which vehicle was not braking)
326 to 405 index numbers array has random energy values. (The time when vehicle was braking and regenerating energy)
and so on. This sequence goes on till nth number of array.
What I want to do is to get starting and ending index number of each set of energy values.
For example the result I must get shall be like
141 - 200
326 - 405
so on...
Latter this time will be used for charging of battery.
Can someone please suggest what method or technique shall I use to get this result.
2 commentaires
Image Analyst
le 4 Déc 2018
Please attach some data for us to work with. Make it easy for us to help you, not hard. This is trivially easy with regionprops() if you have the Image Processing Toolbox.
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Guillaume
le 4 Déc 2018
Modifié(e) : Guillaume
le 4 Déc 2018
startends = find(diff([0, yourarray > 0, 0]));
startends = reshape(startends, 2, [])';
startends(:, 2) = startends(:, 2) - 1
3 commentaires
Guillaume
le 4 Déc 2018
Modifié(e) : Guillaume
le 4 Déc 2018
I have no idea what I was thinking when I wrote the second line. It's not what I intended at all.
Fixed now. You understood how the code works anyway, judging by your comments.
Note that if energyB is a column vector, then:
startends = find(diff([0; energyB > 0; 0]));
will be more efficient than transposing. The rest would stay the same.
Plus de réponses (1)
madhan ravi
le 4 Déc 2018
Modifié(e) : madhan ravi
le 4 Déc 2018
Use logical indexing:
idx=find(values>0) %gives linear indices
values(values>0) %gives you all the values greater than zero
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