Extract element from column vector with condition
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I have column vector
P=[ 0; 212; 111; 190; 0; 223; 123; 200; 189; 219; 0; 190; 175; 202; 167; 181
....and so on]
I want to extract the 2nd and 3rd elements from the left 0 element IF LENGTH BETWEEN TWO 0 (the left 0 and right 0) is GREATER THAN 3. Save 2nd position elements in P2 column vector and 3rd position elements in P3 column vector. The result should be
After extraction, the remaining elements should be placed into P1 such as
P1 = [ 0; 212; 111; 190; 0; 223; 189; 219; 0; 190; 167; 181 ....and so on]
P2 = [123; 175]
P3 = [200; 202]
7 个评论
Image Analyst
2014-8-8
编辑:Image Analyst
2014-8-8
It might be clearer if you said "is 4 or more" rather than is "greater than 3". So the left run has 121, 111, 190 and that's 3, but not more than 3 (not 4 or greater) so those are left alone and get transferred to P1.
It's fairly easy if you have the Image Processing Toolbox. Do you?
采纳的回答
Nir Rattner
2014-8-8
编辑:Nir Rattner
2014-8-8
You can use the “find” function to find the indices of your zeros and then subtract each index by the one before to make sure the distance between them is not too large.
P=[ 0; 212; 111; 190; 0; 223; 123; 200; 189; 219; 0; 190; 175; 202; 167; 181; 0;];
Pzeros = find(P == 0);
violators = Pzeros(find(Pzeros(2 : end) - Pzeros(1: end - 1) > 4));
P1 = P;
P1([violators + 2; violators + 3]) = [];
P2 = P(violators + 2);
P3 = P(violators + 3);
更多回答(2 个)
Azzi Abdelmalek
2014-8-8
编辑:Azzi Abdelmalek
2014-8-8
Edit
P=[ 0; 212; 111; 190; 0; 223; 123; 200; 189; 219; 0; 190; 175; 202; 167; 181 ]
ii=strfind(P'~=0,[0 1])
idx=ii([diff([ii numel(P)])]>4)
P1=P'
jj=[idx+2 idx+3]
P1(jj)=[]
P2=P(idx+2)'
P3=P(idx+3)'
Image Analyst
2014-8-8
Method using the Image Processing Toolbox:
P=[ 0; 212; 111; 190; 0; 223; 123; 200; 189; 219; 0; 190; 175; 202; 167; 181]
P2 = [];
P3 = [];
measurements = regionprops(P~=0, P, 'PixelValues', 'Area')
for k = 1 : length(measurements)
% Show length of this stretch in the command window:
fprintf('Area of stretch #%d = %d\n', k, measurements(k).Area);
% Tack onto P2 and P3 if the length >= 4.
if measurements(k).Area >= 4
P2 = [P2, measurements(k).PixelValues(2)];
P3 = [P3, measurements(k).PixelValues(3)];
end
end
% Show in command window:
P2
P3
3 个评论
Image Analyst
2014-8-12
I'm leaving on a week long trip in an hour. It looks like you've accepted an answer so then just go with that.
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