MATLAB: How to import large data file into matlab

large data

I have very large data 5GB space delimited mixed data (data.prn) with column header:
                         *0000*
                         *0000*
       al      10.598010201     1.890025647
       am      11.222025789    -5.369021654
       as     -10.256862254    11.235854322
       at      14.589056356    15.888792312 
               .           .
               .           .
I know it has three column but i don't know exactly the number of rows since the data is to large to open. My target is to plot data(:,1) vs data(:,2). Any suggestion which command is fast to import the data to matlab.Thanks!

Best Answer

fid = fopen('data.prn', 'rt');
datacell = textscan(fid, '%*s%f%f', 'HeaderLines', 2);
fclose(fid);
plot(datacell{1}, datacell{2})
However, keep in mind that your screen only has a few thousand pixels, not billions, so you are going to end up with multiple data points per pixel, which will be slow and of no good visual purpose. You should consider plotting only a subset of the data, such as
plot(datacell{1}(1:1000:end}, datacell{2}(1:1000:end))
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