# How can i find 4 continuous component in row and replace

2 views (last 30 days)
Triveni on 6 Aug 2016
Commented: Walter Roberson on 8 Aug 2016
I have a row,
I = [60 60 0 0 0 0 45 60 90];
% I want to find 4 continuous component, and 4th component should be replaced with next component from 4th component. Means, 4th component is 0 which is found in column 6, then it should be replace with column 6th i.e 45,
%Just tell me how to find index, i.e I(6).
New_I = [60 60 0 0 0 45 0 60 90];
Image Analyst on 6 Aug 2016
Clear as mud. Too bad because I'm quitting for the day. See my comment above (again), my answer below, and look up regionprops() in the help, particularly the PixelIdxList property.

Image Analyst on 6 Aug 2016
Which zero got replaced? It just looks like you inserted a 45 between the 3rd and 4th zero but there are still 4 zeros like in your original vector.
To find 4 zeros in a row, use bwpropfilt():
I = [60 60 0 0 0 0 45 60 90];
props = bwpropfilt(I == 0, 'Area', 4)
% Now props will = [0 0 1 1 1 1 0 0 0]
% Use that however you want - you're not clear.
% For example
I_new = I; % Initialize
% Replace those zeros with 45's
I_new(props) = 45
##### 2 CommentsShowHide 1 older comment
Walter Roberson on 8 Aug 2016
zidx = find(I==0, 4, 'first');
if length(zidx) < 4
error('I does not have at least 4 zeros');
end
pos_of_4th_zero = zidx(4);

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