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Split array into cell arrays of different size

Asked by lightroman on 1 Nov 2017
Latest activity Edited by Cedric Wannaz
on 2 Nov 2017
I have an array that I am trying to divide into different lengths arrays. The array is 750000 values or so long so I needed an efficient way. I want to start the next array when pattern finishes or begins to start over.
An example would be
A = [5 19 43 28 5 19 43 5 19 43 28 5 19 5 19 43]
I want the result to be something like
Result = {5 19 43 28} {5 19 43} {5 19 43 28} {5 19} {5 19 43}
However, it can also be a longer pattern, [5 19] is how I know the pattern restarts because these values only occur at the beginning of each data set.

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1 Answer

Answer by Cedric Wannaz
on 1 Nov 2017

>> seqs = mat2cell( A, 1, diff( [strfind(A, [5,19]), numel(A)+1] ))
seqs =
1×5 cell array
{1×4 double} {1×3 double} {1×4 double} {1×2 double} {1×3 double}

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I get an error saying PATTERN must be a string or cell array of strings, evaluating arg list element 1 .... element 3.
Any idea why? Using same code as I have posted with your solution.
Which version of MATLAB are you using? STRFIND has been working with numeric array for a long time.
seqs = mat2cell( A, 1, diff( [find(A(1:end-1)==5 & A(2:end)==19), numel(A)+1] ))
and if you need to be more flexible about the size of start patterns, we can generalize the call to FIND, but for this I'll need to know your version of MATLAB.

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