Remove rows in a \addplot table command

Question

Is there any way to adapt Show last N rows from input datafile only in \pgfplotstabletypeset to a \addplot table command ?

This doesn't work:

\documentclass{article}

\usepackage{pgfplots}
\usepackage{filecontents}

\begin{document}

\begin{filecontents}{data.dat}
1 5
2 3
3 6
4 4
5 0
6 1
\end{filecontents}

\pgfkeys{
    /pgfplots/table/print last/.style={
        row predicate/.code={
            % Calculate where to start printing, use `truncatemacro` to get an integer without .0
            \pgfmathtruncatemacro\firstprintedrownumber{\pgfplotstablerows-#1}
            \ifnum##1<\firstprintedrownumber\relax
                \pgfplotstableuserowfalse
            \fi
        }
    },
    /pgfplots/table/print last/.default=1
}

\begin{tikzpicture}
  \begin{axis}[x=1cm]
    \addplot table {data.dat};
  \end{axis}
\end{tikzpicture}

\begin{tikzpicture}
  \begin{axis}[x=1cm]
    \addplot table [print last=4] {data.dat};
  \end{axis}
\end{tikzpicture}

\end{document}

Both plots are the same:

Answer 1

Here's a style plot last=<n> that can be added to the \addplot table [<options>]. It uses the create on use syntax to create a new column which checks whether the current row is less than n rows from the final row, assigns the value of that check to meta, and then uses a filter to only keep the values for which meta is 1.

\begin{tikzpicture}
  \begin{axis}[x=1cm]
    \addplot table {data.dat};
  \end{axis}
\end{tikzpicture}

\begin{tikzpicture}
  \begin{axis}[x=1cm]
      \addplot table [plot last=4] {data.dat};
  \end{axis}
\end{tikzpicture}

will yield

The main advantage over this approach is that you don't need to explicitly call \pgfplotstablegetrowsof before your plot, and you don't need to specify the data file twice. The main drawback is that you can't use the meta entry anymore for plotting error bars or changing the colour in a scatterplot.

Here's the full code:

\documentclass{article}

\usepackage{pgfplots}
\usepackage{pgfplotstable}
\usepackage{filecontents}

\begin{document}

\begin{filecontents}{data.dat}
a b
1 5
2.5 3
3 6
4 4
5 0
6 1
\end{filecontents}

\pgfkeys{
    /pgfplots/table/print last/.style={
        row predicate/.code={
            % Calculate where to start printing, use `truncatemacro` to get an integer without .0
            \pgfmathtruncatemacro\firstprintedrownumber{\pgfplotstablerows-#1}
            \ifnum##1<\firstprintedrownumber\relax
                \pgfplotstableuserowfalse
            \fi
        }
    },
    /pgfplots/table/print last/.default=1,
    /pgfplots/table/plot last/.style={
        create on use/rows/.style={
            create col/expr=\pgfplotstablerow>(\pgfplotstablerows-#1-1)
        },
        meta=rows,
        /pgfplots/x filter/.code=\pgfmathparse{x/meta}
    }
}

\begin{tikzpicture}
  \begin{axis}[x=1cm]
    \addplot table {data.dat};
  \end{axis}
\end{tikzpicture}

\begin{tikzpicture}
  \begin{axis}[x=1cm]
      \addplot table [plot last=4] {data.dat};
  \end{axis}
\end{tikzpicture}


\end{document}

Answer 2

Thanks Christian, you pointed me to a solution that works. This is the edited and corrected code:

\documentclass{article}

\usepackage{pgfplots}
\usepackage{filecontents}

\begin{document}

\begin{filecontents}{data.dat}
1 5
2 3
3 6
4 4
5 0
6 1
\end{filecontents}

\begin{tikzpicture}
  \begin{axis}[x=1cm,y=1cm]
    \addplot table {data.dat};
  \end{axis}
\end{tikzpicture}

\begin{tikzpicture}
    \pgfplotstablegetrowsof{data.dat}
    \pgfmathsetmacro\yfin{\pgfmathresult - 4}
    \pgfmathsetmacro\yini{0}

    \begin{axis}[x=1cm,y=1cm,skip coords between index={\yini}{\yfin}]
        \addplot table {data.dat};
    \end{axis}
\end{tikzpicture}

\end{document}