select several groups in a Vector

Question

hamed 2017-9-6

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/355428-select-several-groups-in-a-vector

编辑： hamed 2017-9-6

采纳的回答： Stephen23

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Hi all

I have a vector like this:

x=[0 0 0 1 1 1 0 0 1 1 0 1 1 1 0 0 0 0 1 1 1 1]

I'm trying to save each part of ones in a Row. for instance, the result of this vector should be a matrix with 4 rows.

1th row = 1 1 1
2th row = 1 1
3rd row = 1 1 1
4th row = 1 1 1 1

how can I do that automatically with a loop.

could you please help me.

Cheers

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Stephen23 2017-9-6

"the result of this vector should be a matrix with 4 rows."

That is impossible, as all rows of a matrix must have the same number of elements. Instead you could:

store the vectors in a cell array.
pad each vector with some value (e.g. see padcat).

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Answer 1

Stephen23 2017-9-6

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/355428-select-several-groups-in-a-vector#answer_280467

编辑：Stephen23 2017-9-6

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Method one: diff and arrayfun:

>> x = [0 0 0 1 1 1 0 0 1 1 0 1 1 1 0 0 0 0 1 1 1 1];
>> d = diff([0,x,0]);
>> C = arrayfun(@(b,e)x(b:e-1),find(d>0),find(d<0),'uni',0);
>> C{:}
ans =
   1   1   1
ans =
   1   1
ans =
   1   1   1
ans =
   1   1   1   1

Method two: regexp and cellfun:

>> C = regexp(char(x),sprintf('\1+'),'match');
>> C = cellfun(@double,C,'uni',0);
>> C{:}
ans =
   1   1   1
ans =
   1   1
ans =
   1   1   1
ans =
   1   1   1   1

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hamed 2017-9-6

编辑：hamed 2017-9-6

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Thanks a lot Stephen

The code that you sent me works perfectly. Actually, I have a vector of the numbers like the following vector:

X=[NaN NaN 2.66 3.12 1.03 NaN NaN NaN -2.66 1.32 -0.14 NaN 3.55 -0.25]);

For this vector, I should categorize indexes of each group of numbers separately in a vector for example:

Z(1,:)= [3 4 5]
Z(2,:)= [9 10 11]
Z(3,:)= [13 14]

I'd like to make a code to search on the vector and find the indexes of continuous numbers, each zero or NaN cuts the chain of numbers and the first next group should categorize in the next row. I've tried to solve this problem with your code but I can't.

Best Regards,

Hamed

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