How to extract values from an array?

2022 3 9
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更新时间：2022 3 9
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Hello all,
I have an array with values that repeat , is it possible to determine the start and end points of a particular value in the array. For example
array = [10 10 10 30 30 30 30 30 4 4 4 4 4 30 30 30 30 30 30 2 2 2 2 2 30 30 30 30];
the goal is to extract those values in between the 30s.
How can i go about this? Thanks

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Rik
Rik 2022-3-9
What would be the intended output? Perhaps this?
new_array=[4 2];
You can probably use most of the RunLength function Jan published on the file exchange.
Daniel Adeniyi
Daniel Adeniyi 2022-3-9
let me check out the RunLength function. i want to use the indices of the start and end 30 to extract the values in between to a new array. Thanks
Rik
Rik 2022-3-9
If you want to extract the numbers, do you mean you want [4 2], or [4 4 4 4 4 2 2 2 2 2];? (or something else)
That is also probably important information if David's answer doesn't work for you.
Daniel Adeniyi
Daniel Adeniyi 2022-3-9
Yes you are right, I would want as output [4 4 4 4 4 2 2 2 2 2].

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Rik
Rik 2022-3-9
Ran in:

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Ran in:
Using RunLength by Jan:
array = [10 10 10 30 30 30 30 30 4 4 4 4 4 30 30 30 30 30 30 2 2 2 2 2 30 30 30 30];
%first select only the parts between the first and last 30
new_array=array(find(array==30,1,'first'):find(array==30,1,'last'));
[B, N] = RunLength(new_array)
B = 1×5
30 4 30 2 30
N = 5×1
5 5 6 5 4
%remove the 30s
L=B==30;
B(L)=[];
N(L)=[];
%decode back to the normal array
new_array = RunLength(B, N)
new_array = 1×10
4 4 4 4 4 2 2 2 2 2

更多回答（1 个）

David Hill
David Hill 2022-3-9

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a=num2str(yourArray==30);
a=a(a~=' ');
[s,f]=regexp(a,'[1]*');
new_array=[s,f];

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Daniel Adeniyi
Daniel Adeniyi 2022-3-9
Is it possible to have an output such as [4 4 4 4 4 2 2 2 2 2] instead of their unique value.

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