Select non consecutive rows for addplot in tikz

Question

I have a list of points in a table out of which I would like to plot several closed loop paths. For each \addplot I would like to give an index list for this particular path.

The trouble is that these points aren't necessarily given as consecutive index numbers. So, I tried to combine the ideas from here and here. For each \coordindex it should be checked if it is a member of the desired list, if not it is discarded. This is what I tried

\documentclass[11pt,a4paper]{article}
\usepackage{pgfplots}
\usepackage{pgfplotstable}
\usetikzlibrary{calc,patterns}

\newif\ifmember
\makeatletter
\newcommand{\MemberQ}[2]{\global\memberfalse%
    \edef\temp{#2}%
    \@for\next:=#1\do{\ifx\next\temp\relax\global\membertrue\fi}}
\makeatother

\pgfplotsset{compat=1.14, select coords/.style 1 args={
x filter/.code={
    \MemberQ{#1}{\coordindex}
    \ifmember \else \def\pgfmathresult{}\fi
}
}
}

\begin{document}
\pgfplotstableread[]{
x   y   lab
10  10  A
20  10  B
20  20  C
10  20  D
}\mytable

\begin{tikzpicture}
\begin{axis}[]
\addplot [pattern color=blue,pattern=horizontal lines,select coords ={0,2,3}] table {\mytable}--cycle;
\end{axis}
\end{tikzpicture}
\end{document}

The result is an error "Illegal parameter number in definition...". Can anyone help?

Many thanks.

Select non consecutive rows for addplot in tikz

0 Answers0