Computation on arrays using loops
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Kacper Witasinski
on 19 Feb 2021
Edited: Kacper Witasinski
on 23 Feb 2021
Hello,
I want to create code that will do operations on specified values from the arrays. I have array X and array Y, where array Y is X-dependent. Array X looks more or less like this: [0 0 0 0 0 0 0 0 0 0 0 45.9 45.98 45.99 46 46 46 46 0 0 0 0 0 0 0 ...], it represents pulse-like behaviour. I want matlab to save in workspace the values of array Y that corresponds to the every last "0" of the array X before the pulse ''46'' happens on the length of the whole array.
I expect that for/while loop has to be applied, but I am not sure which one and how the statements should look like. I would appreciate any help. Thank You. I am using matlab2020b version.
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Accepted Answer
Stephen23
on 19 Feb 2021
Y = [2.659717,2.656496,2.656496,2.656173,2.662294,2.661328,2.660039,2.620416,2.614295,2.606242,2.600765,2.600443,2.590779,2.591745,2.590457,2.586913,2.58498,2.583048,2.585303,2.578216,2.577571,2.580793,2.57886,2.573061,2.575638]
X = [0,0,0,0,0,0,0,46.24,46.24,46.24,46.24,46.24,46,46,46,46,46,45.99,45.99,45.99,45.99,45.99,46,46,46,46,46,46,46,46,46,46,46]
idx = diff(X~=0)>0;
out = Y(idx)
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More Answers (2)
Steven Lord
on 22 Feb 2021
Since you seem to be describing change point detection, see the ischange function and/or the Find Change Points task in the Live Editor.
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KALYAN ACHARJYA
on 19 Feb 2021
Edited: KALYAN ACHARJYA
on 19 Feb 2021
"I want matlab to save in workspace the values of array Y that corresponds to the every last "0" of the array X before the pulse ''46'' happens on the length of the whole array."
Is this? Note for this problem loop can be avoided
idx=find(diff(X)==-46)+1
This idx gives the indices of x, where x equal to zero and it's corresponding previous data to be equal to 46
Afterwards
Y=X(idx)
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KALYAN ACHARJYA
on 19 Feb 2021
Edited: KALYAN ACHARJYA
on 19 Feb 2021
Yes as per my code gives transition indices (from 46 to 0 only)
Can you clarify again? In this X example, what would be the Y
X=[0 0 0 0 0 0 0 0 0 0 0 45.9 45.98 45.99 46 46 46 46 0 0 0 0 0 0 0 ]
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