MATLAB Answers

1

How to count consuctive 0's inbetween values of 1

Asked by Chris E. on 17 Oct 2012
I have really long code that does what I want, but I wanted to try to find a faster code to do this, for loop is taking forever. for example I have a vector of:
count = [0; 1; 0; 0; 0; 1; 0; 1; 1; 1; 0; 0; 0; 1; 0; 1; 1; 0; 0]
What I would like for an answer is the consecutive 0's between the ones... so,
ans =
1
3
1
0
0
3
1
0
2
Here is what I have to do it, (count coming in is the 1 and 0 vector list), the output is "store":
for m = 1:size(count,1)
store = 0;
countlast = 0;
j = 0;
if (sum(count)>=1)
for n = 1:size(count,1)
if count(n) == 0
countlast = countlast + 1;
else
j = j + 1;
store(j) = countlast;
countlast = 0;
end
end
j = j + 1;
store(j) = countlast;
end
end
store'
If there is a faster way of doing this Please help me out! Thanks, Chris

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3 Answers

Answer by Kye Taylor
on 17 Oct 2012
Edited by Kye Taylor on 17 Oct 2012
 Accepted Answer

This is a fun one.
Try
count = reshape(count,1,[]); % make it a row vector
store = [nnz(cumsum(count)==0),...
diff(find(count))-1,...
nnz(cumsum(count)==max(cumsum(count)))-1]

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Thanks a ton! glad you found it fun...

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Answer by Sean de Wolski
on 17 Oct 2012

v = [0; 1; 0; 0; 0; 1; 0; 1; 1; 1; 0; 0; 0; 1; 0; 1; 1; 0; 0;1];
vzcount = diff(find([1;v;1]))-1; %find ones in a [1;v;1] vector and take the difference -1
%Remove zeros from first or last element
if vzcount(1)==0;
vzcount = vzcount(2:end);
end
if vzcount(end) == 0;
vzcount = vzcount(1:end-1);
end

  1 Comment

Thanks for the help too!

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