Re: How to print long integers through Octave script in terminal?

[Sebastian Schöps]

> Well my script is extremely simple, I am trying to open a file with long 
> values more than 6 digits after the decimal position. Sample of file: 
[...]
> It only prints the first 6 digits after I want to print more than 6 like 15 
> digits which is the max of a long format float. 
> 
> Well on matlab the syntax that I am using is: 
> 
> test_1 = importdata('output.txt'); 
> column_1 = test_1(:,5); 
> 
> Which extracts the 5th column of the *.txt file. 
> 
> So I am also wondering how can I do that on Octave, extract only the 5th 
> column. 

Dear Thanos, 

it seems that you are confusing integers and floating point numbers. I guess 
that you want to print long *floats*? But be warned, it is not wise to care 
about the last digit of a very long floating point number. If you are not aware 
of this please read e.g. http://en.wikipedia.org/wiki/Floating_point and maybe 
http://en.wikipedia.org/wiki/Machine_epsilon before messing around with data.

To answer your question: I recommend to use "fprintf" as described at 
http://www.gnu.org/software/octave/doc/interpreter/Formatted-Output.html
to format output. This gives more control than using "format long".

The following works in Octave and Matlab and should help you to get started

%-----
% read tabular data from file
table = load ('output.txt','-ascii'); 
% loop over all columns and print
for col=1:size(table,2)
fprintf('Column %d\n',col);
fprintf('%.6f\n',table(:,col)); 
end
%-----

Bye
Seb.



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