Re: reading ASCII data file

[Andrew Wittenberg <andyw@xxxxxxxxxxxxxxxxxxxx>]

On Sun, 20 May 2001, Irina Marinov wrote:

> I have many ASCII data files which have a header of 8 lines, 3 columns of
> data and then some 8 lines of unwanted text. Is there any way to skip the
> 8 lines of text at the end ? The command 
>    set data/ez/skip=8/columns=3/var="depth,data,stdev" mydataset.dat 
> doesn't work because I have those 8 lines of unwanted text at the end. 

Hi Irina, 

Here are two suggestions.

1) Define an input grid within Ferret:
yes? sp echo "let n =" \`wc mydataset.dat | awk '{print $1}'\` > tmp.jnl
yes? go tmp
yes? def axis/x=1:`n-16`:1 xax 
yes? def grid/x=xax g
yes? set data/ez/skip=8/col=3/var="depth,data,stdev"/grid=g mydataset.dat

This method gives you explicit control over the grid that the data is
placed on -- you can change the "def axis" command to suit your needs.

- or -

2) Remove the offending lines outside of Ferret:
Save the following shell script as "cut_last":

# Shell script: cut_last
# Usage: cut_last nlines filename
set keep = `wc $2 | awk '{print $1}'`
@ keep = $keep - $1
head -n $keep $2 > $2.cut

Then at the shell prompt do 

% chmod +x cut_last
% cut_last 8 mydataset.dat

This method lets you read the resulting "mydataset.dat.cut" using your
original idea.  The results will be placed on Ferret's "EZ" grid.

Good luck!

Andrew

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Andrew Wittenberg          Program in Atmospheric and Oceanic Sciences
andyw@splash.princeton.edu                        Princeton University
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