MATLAB: How to delete row based on the value of row (i) and row (i+1)

deleting row in matrix

Hi I am new to matlab, I am working with 1000*10 matrix. I want to delete the all row if the value in row (i) column 10 is the same as the value in row (i+1) column 10, and keep the row if the value in row (i) column 10 is not equal to the value in row (i+1) column 10. For example: my data file is X. and my code is, but it does not work with me :
for i=1:length (X)
  if (X(i,10)~=X(i+1,10)
      y(j,1:10)= X(i,1:10);
j=j+1;
else 
 y(j,1:10)=[];
end 
if true
  % code
end
end

Best Answer

I think this is what you are asking for (i.e., delete all rows that have equal neighbors in column 10):
X = your matrix
n = 10; % the column to use for the comparison
d = diff(X(:,n)); % the 0's in d indicate where neighbors are equal to each other
d = [d;1] .* [1;d]; % vector that has 0's for all rows that are equal to neighbors
X(~d,:) = []; % delete the rows that have equal neighbors using logical indexing
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