[pstricks] ignore first n rows with \readdata

[Herbert Voss]

----- Original Message -----

>From: "Patrick Drechsler" <patrick at pdrechsler.de>
>To: <pstricks at tug.org>
>Sent: Thursday, March 31, 2005 11:10 PM
>Subject: Re: [pstricks] ignore first n rows with \readdata
>  
>
>>The only drawback is that one has to know the column
>>names. Ignoring the first line would be easier (for the
>>user). But I have no idea if this is possible in postscript.
>>
>>For my current work your solution is fine, since I do not have to
>>delete the first line in my data sets.
>>

try this demo

Herbert

\begin{filecontents*}{demo9.dat}
some nonsense in this line äöüÖÜß
time forcex forcey
0 0.2
1 1
2 4
\end{filecontents*}
%
\documentclass[a4paper]{article}

\usepackage{pstricks}
\usepackage{pst-plot}
\usepackage{pst-xkey}

\makeatletter
\define at key[psset]{}{ignoreLines}{\def\psk at ignoreLines{#1}}
\psset{ignoreLines=0}
%
\def\readdata{\@ifnextchar[{\readdata at i}{\readdata at i[]}}
\def\readdata at i[#1]#2#3{%
  \psset{#1}
  \openin1=#3
  \begingroup
  \def\pst at tempg{}%
  \ifeof1
    \@pstrickserr{Data file `#3' not found.}\@ehpa
  \else
    \pst at datadelimiters
    \catcode`\[=1
    \catcode`\]=2
    \pst at cnta=0
    \loop \ifnum\the\pst at cnta<\psk at ignoreLines
      \advance\pst at cnta by 1\relax
      \read1 to \pst at tempa
    \repeat
    \typeout{>>> ignored \the\pst at cnta\space data lines}
    \readdata@%
  \fi
  \endgroup
  \let#2\pst at tempg
  \global\let\pst at tempg\relax
  \ignorespaces}
\makeatother

\begin{document}

\readdata[ignoreLines=2]{\data}{demo9.dat}
%\readdata{\data}{data.dat}
\pspicture(2,4)
  \listplot[showpoints=true]{\data}
  \psaxes{->}(2,4)
\endpspicture
\end{document}