reading data from ascii files.

[Veloci]

Hi everyone,

I know that the topic sounds familiar to many of you, so i apologize for any
annoyance it may cause.
My problem with the data input is not so much the "what functions to use",
more like "making it faster". 
Starting point are a couple of data files in ascii format with a specified
number of header rows (data on the experiment and so on) followed by a
unspecified number of data-rows (depending on the measurement time and the
sampling rate i use). 
What i want to do: I want to implement a automated input of these data files
into octave matrices and calculate data from these (as the most people
would).
What i want to use for that: The most promising function seems to be
"dlmread", as my data is organised in rows with a fixed number of columns
and a fixed delimiter.
My problem: As the number of rows is not specified, i can't give dlmread a
range vector with the coordinates of the last row. This is not a tragic
problem for dlmread, because it still works with only the starting row and
column, but it is a rather time consuming matter concerning the huge data it
has to read. It would be much faster if i could allocate the needed memory
in a zero matrix with the size of the data. For this i need to know the
number of rows in my ascii file. You could say, "Open the file in a good
editor and seek for the end of rows". That would be a solution for manual
data processing, but not for a automated procedure. 
The solution i seek: I've searched on the net for a solution to my problem,
but i couldn't find anything that would be possible in Octave. In MATLAB
there was a possibility with memmapfile, that calculates the number of rows
in a file. But memmapfile is not implemented in Octave. So i tried to find
something similar, but couldn't find any example. I could imagine using the
"eof"-pointer, but i don't know how to calculate the end row from that
position.  

If there is any solution that you could suggest, it would be much
appreciated.

Greetings,
Veloci

PS: Please don't consider calling any linux functions, because i am limited
to a WinXP as OS. Sorry! 

-- 
View this message in context: 
http://octave.1599824.n4.nabble.com/reading-data-from-ascii-files-tp2291167p2291167.html
Sent from the Octave - General mailing list archive at Nabble.com.