Removing replication in matlab

Hi guys, I have string like this

str= '000000011111100000000000000000000000000000000000111111100000000000000000000011110000000000000000000000000001111111001101'

I want to remove replication of zero and ones in that string this means , the output would be like this '010101010101' without replication of zero or ones ... *be careful that I dont know number of replication of zeros or ones in the str string ...

any help please how can I do that in matlab? thanks alot.

Answer 1

[madhan ravi]

 regexprep(str,{'0+','1+'},{'0','1'})

[Mohamed Jamal]

Appreciated!!!!!!

could you please and I appreciate your effort much ! to help me here : https://www.mathworks.com/matlabcentral/answers/564524-problem-in-matlab-implementation-zero-crossings-detector?s_tid=prof_contriblnk

thanks alot

[John D'Errico]

Better than my solution of course.

Answer 2

[John D'Errico]

But the string, after you remove the replicates will always be identically the same, just alternating 0's and 1's. If the first element is a '0', then the string will be '010101010...'. If the first element is a 1, then it will be opposite. The only question is the length of the string.

My point is, don't even worry about removing the replicated elements. Just create the final result as it must be.

newstr = str(1);
if newstr == '0'
  % Count the number of '10' transitions
  newstr = [newstr,repmat('10',[1,numel(strfind(str,'10'))])];
  
  % was the final element a '1'
  if str(end) == '1'
    newstr = [newstr,'1'];
  end
else
  % then the first element was a '1'
  % So count the number of '01' transitions
  newstr = [newstr,repmat('01',[1,numel(strfind(str,'01'))])];
  
  % was the final element a '0'
  if str(end) == '0'
    newstr = [newstr,'0'];
  end
end

For example, with str as in your example, this produces:

newstr =
    '010101010101'

[Mohamed Jamal]

Hi all good, I have took this into consideration, already done it ! anyone I appreciate your effort!

could you please help me here because Im really stuck! , it's not good to share you here but any assistance would be appreciated:

https://www.mathworks.com/matlabcentral/answers/564524-problem-in-matlab-implementation-zero-crossings-detector?s_tid=prof_contriblnk