Parameterizing color in \addplot

Question

From reading Tikz and PGFPlots manuals I got an impression that using multiple loop variables syntax in \foreach I should be able to change color of the plots using \clr loop variable in \addplot parameters:

\documentclass{article}
\usepackage{tikz,pgfplots}

\begin{document}

    \begin{tikzpicture}[font=\tiny]
        \begin{axis}[
            axis x line=center,
            axis y line=center,
            restrict y to domain=-100:100,
        ]
        \foreach \d/\clr in {1/orange, 2/red, 3/green, 4/blue, 5/brown}
        {
            \addplot[smooth,\clr,domain=-5:5]{(x-\d)^3};
        }
        \end{axis}
    \end{tikzpicture}

\end{document}

That did not work. What am I missing?

Answer 1

This is an expansion issue (and I not the right person to attempt to explain it). But, a way to get the desired results is to use \pgfplotsinvokeforeach which expands the contents of its body. I used xstring to parse the two components, but other techniques can be used as well.

Notes:

• When using short macro names it is best to make sure you are not overwriting existing commands, thus the \newcommands. This technique would have shown that \d is an existing macro.

Code:

\documentclass[border=2pt]{standalone}
\usepackage{tikz,pgfplots}
\usepackage{xcolor}
\usepackage{xstring}
\pgfplotsset{compat=newest}
\newcommand{\diff}{}% Ensure it is not already defined
\newcommand{\clr}{}% Ensure it is not already defined
\begin{document}
\begin{tikzpicture}[font=\tiny]
    \begin{axis}[
        axis x line=center,
        axis y line=center,
        restrict y to domain=-100:100,
    ]
    \pgfplotsinvokeforeach{1/orange, 2/red, 3/green, 4/blue, 5/brown}
    {
        \StrBefore{#1}{/}[\diff]%
        \StrBehind{#1}{/}[\clr]%
        \edef\AddPlot{\noexpand\addplot[thick,smooth,color=\clr,domain=-5:5] {(x-\diff)^3};}%
        \AddPlot
    }
    \end{axis}
\end{tikzpicture}


\end{document}