# Nested ifnum conditional groupplots with pgfplots?

I want to use groupplots, and set a variable to conditionally plot the plots. Here is the minimal non-working example:

\documentclass{article}
\usepackage{pgfplots}
\usetikzlibrary{calc}
\usepgfplotslibrary{groupplots}
\def\a{1}
\begin{document}
\begin{tikzpicture
\begin{groupplot}[group style={group size=1 by \a},height=3cm,width=6cm]
\ifnum\a>0{ %
\nextgroupplot[title=One]
\addplot coordinates {(0,0) (1,1) (2,2)};
\ifnum\a>1{ %
\nextgroupplot[title=Two]
\addplot coordinates {(0,2) (1,1) (2,0)};
\ifnum\a>2{ %
\nextgroupplot[title=Three]
\addplot coordinates {(0,2) (1,1) (2,1)};
\ifnum\a>3{ %
\nextgroupplot[title=Four]
\addplot coordinates {(0,2) (1,1) (1,0)};
}\fi
}\fi
}\fi
}\fi
\end{groupplot}
\node (title) at (0,0) {THE Title};
\end{tikzpicture}
\end{document}

This fails with:

! Extra }, or forgotten \endgroup.
l.24     }
\fi

Not sure if it's because of the nested \ifnums, or because of \nextgroupplot; if the first \nextgroupplot is commented, error is now:

! Undefined control sequence.
coordinates {(0,0) (1,1) (2,2)};

Can such a conditional plotting of group plots be done?

Drop the use of groups inside the groupplot construction. I've added some indentation, and corrected the small type (missing } at the beginning of the tikzpicture environment):

\documentclass{article}
\usepackage{pgfplots}
\usetikzlibrary{calc}
\usepgfplotslibrary{groupplots}
\def\a{3}
\begin{document}
\begin{tikzpicture}
\begin{groupplot}[group style={group size=1 by \a},height=3cm,width=6cm]
\ifnum\a>0
\nextgroupplot[title=One]
\addplot coordinates {(0,0) (1,1) (2,2)};
\ifnum\a>1
\nextgroupplot[title=Two]
\addplot coordinates {(0,2) (1,1) (2,0)};
\ifnum\a>2
\nextgroupplot[title=Three]
\addplot coordinates {(0,2) (1,1) (2,1)};
\ifnum\a>3
\nextgroupplot[title=Four]
\addplot coordinates {(0,2) (1,1) (1,0)};
\fi
\fi
\fi
\fi
\end{groupplot}
\end{tikzpicture}
\end{document}
• Fantastic, @Werner - works like a charm! :) I used the groups in the first place, because I was afraid \ifnum wouldn't work with groups of commands without them - but your solution shows it actually works fine like that. Many thanks! – sdaau Mar 22 '14 at 4:53