Deleting rows in a matrix with condition on its column value

Hi there,

I have a text file with about 14 millions rows and 11 columns. On the 11th column, there are values that are really small.. and I want to get rid of the rows that their 11th column has a value that is smaller than 10^-(12).

I loaded the file into matlab and now it's stored in a variable as a matrix with 14 million rows and 11 columns.. and I wrote this code but it is so painfully slow that it takes it about 1 second per row.. so that's 150 days for the whole matrix.

that's my slow code:

for i = 1 : 13847014

    if New_LongDataUn(i,11) < 10^-(12) 
         New_LongDataUn(i,:) = [];
    end
end

Thanks for all the kind help you guys!

Answer 1

[James Tursa]

New_LongDataUn(New_LongDataUn(:,11) < 1e-12,:) = [];

[itzhak mal]

thank you! smooth and quick!!!!

do you happen to know how i can save this matrix as a data so i wouldn't have to do that every time?

[James Tursa]

If you mean into a mat file, then simply

save your_matfile_name New_LongDataUn

[itzhak mal]

thanks again! so so much!