Removing zeros from a binary array if length of zeros is lesser than a value

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Hello,
I have an array:
input = [0;0;0;0;0;0;0;1;0;1;1;1;0;0;0;0;0;0;1;1;0;0;0;0]
I would like to remove only the 0's between the 1's if the stretch of 0's is lesser than 5, between the 1's. So, for this instance, the output would look something like:
output = [0;0;0;0;0;0;0;1;1;1;1;0;0;0;0;0;0;1;1;0;0;0;0].
Any help would be appreciated.
Thanks!

Accepted Answer

KSSV
KSSV on 19 Feb 2020
input = [0;0;0;0;0;0;0;1;0;1;1;1;0;0;0;0;0;0;1;1;0;0;0;0] ;
idx = input==1; % get the locations of 1
% split zeros and one's into cell
idr = diff(find([1;diff(idx);1]));
D = mat2cell(input,idr(:),size(input,2));
% get the lengths of each cell
L = cellfun(@length,D) ;
L(2:2:end) = NaN ; % make length of 1's NaN as it is not needed
% get the length of zeros which are less then 4
id = L<4 ;
% remove those zeros
D(id) = [] ;
% convert to matrix
output = cell2mat(D) ;
  5 Comments
Meghana Balasubramanian
Meghana Balasubramanian on 19 Feb 2020
Stephen,
Some of the cells have zeros of varying lengths. Replacing it with {1} would simply reduce the entire cell content to 1. Should I run a for loop to find and replace the zero's between the 1's using values stored in "L = cellfun(@length,D);" ?

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More Answers (1)

Raymond MacNeil
Raymond MacNeil on 19 Feb 2020
k = [0;0;0;0;0;0;0;1;0;1;1;1;0;0;0;0;0;0;1;1;0;0;0;0];
y = regexp(num2str(k)', '(?<=[0]{5,})0*', 'split');
z = strjoin(cellfun(@(x) replace(x, '', ' '), y, 'UniformOutput', false));
out = str2num(z)';
  1 Comment
Raymond MacNeil
Raymond MacNeil on 19 Feb 2020
Edited: Raymond MacNeil on 19 Feb 2020
Could also use regexprep. I realize I added more steps than was necessary. Also, other ways exist that don't require regexp. This just happened to be the first solution that came to mind.

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