Using a pre-defined list inside a pgfplotset style

Question

I would like to place defined markers on certain datapoints in a plot using a predefined list of tuples \def\datalist{datapoint/mark}. I found a suitable solution of the same problem with labels which relies upon the nodes near coords. Unfortunately, it works only if the datalist is explicitly contained in the addplot+[nodes near some coords={datapoint/mark}]. The code does not compile if the macro \datalist is used directly in addplot+[nodes near some coords=\datalist]. I guess a solution is related to Using Macro Defined Lists in TikZ/PGFplots but none of the workarounds worked for me.

A MWE:

\documentclass[tikz,border=10pt]{standalone}
\usepackage{pgfplots}
\usetikzlibrary{shapes}
\def\datalist{0/rectangle,
           2/circle,
           4/diamond}
\pgfplotsset{
    compat=1.16,
    %%% 
    node near coord/.style args={#1/#2}{% Style for activating the label for a single coordinate
        nodes near coords*={
            \ifnum\coordindex=#1 \fi
        },
        scatter/@pre marker code/.append code={
            \ifnum\coordindex=#1 \pgfplotsset{every node near coord/.append style=fill, draw,#2}\fi
        }
   },
   nodes near some coords/.style={ % Style for activating the label for a list of coordinates
       scatter/@pre marker code/.code={},% Reset the default scatter style, so we don't get coloured markers
       scatter/@post marker code/.code={},%
       node near coord/.list={#1}% Run "node near coord" once for every element in the list
   }
}
\begin{filecontents}{datafile.csv}
1.00    1.00
2.00    2.00
3.00    3.00
4.00    4.00
5.00    5.00
\end{filecontents}
\begin{document}
\begin{tikzpicture}
  \begin{axis}[]
      \addplot
      +[
          %nodes near some coords=\datalist, % doesn't compile, returns 'File ended while scanning use of \pgfkeys@code. \par  mwe.tex'
          nodes near some coords={0/rectangle,  % works
                                 2/circle,
                                 4/diamond}, 
      ]
        table []{datafile.csv};
\end{axis}
\end{tikzpicture}
\end{document}

score 3 · Accepted Answer · 2020-12-09T15:30:22.693

You need the /.expanded key handler, i.e. nodes near some coords/.expanded=\datalist.

\documentclass[tikz,border=10pt]{standalone}
\usepackage{pgfplots}
%\pgfplotsset{compat=1.17} %<-consider adding
\usetikzlibrary{shapes}
\def\datalist{0/rectangle,
           2/circle,
           4/diamond}
\pgfplotsset{
    compat=1.16,
    %%% 
    node near coord/.style args={#1/#2}{% Style for activating the label for a single coordinate
        nodes near coords*={
            \ifnum\coordindex=#1 \fi
        },
        scatter/@pre marker code/.append code={
            \ifnum\coordindex=#1 \pgfplotsset{every node near coord/.append style=fill, draw,#2}\fi
        }
   },
   nodes near some coords/.style={ % Style for activating the label for a list of coordinates
       scatter/@pre marker code/.code={},% Reset the default scatter style, so we don't get coloured markers
       scatter/@post marker code/.code={},%
       node near coord/.list={#1}% Run "node near coord" once for every element in the list
   }
}
\begin{filecontents}[overwrite]{datafile.csv}
1.00    1.00
2.00    2.00
3.00    3.00
4.00    4.00
5.00    5.00
\end{filecontents}
\begin{document}
\begin{tikzpicture}
  \begin{axis}[]
      \addplot
      +[
          nodes near some coords/.expanded=\datalist, % works
      ]
        table []{datafile.csv};
\end{axis}
\end{tikzpicture}
\end{document}

The second thing solved the issue and it runs like a charm, thank you :)! The first thing is a typo that slipped in during cut-pasting. I suggest editing the =-part in the question and the answer. Would you agree @lazy-squirrel? — fafroo, Dec 09 '20 at 08:39

Using a pre-defined list inside a pgfplotset style

1 Answers1