latex table variable/optional many arguments

Question

I would like to create a new tabular environment that allows me to add n (1-10) arguments without adding extra columns (such that both examples below work).

Here is my code:

\documentclass{article} 
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[sfdefault]{AlegreyaSans}
\RequirePackage{booktabs}
\usepackage[table,x11names,dvipsnames,table]{xcolor}
\usepackage{tabularx}

\definecolor{mygreen}{RGB}{126,169,105}
\definecolor{myblue}{RGB}{9,28,87}

\begin{document}

\newenvironment{tabulargreen}[3]
  { 
% \renewcommand{\tempcaption}{#3}
 \rowcolors{1}{mygreen!20}{mygreen!10}
   \begin{tabular}{lcr}
   \rowcolor{mygreen}
   \textcolor{white}{\bfseries #1} & \textcolor{white}{\bfseries #2} & \textcolor{white}{\bfseries #3} \\
   }
  {
%      \caption{\tempcaption}
   \end{tabular}
   }

\begin{tabulargreen}{Name}{Zahl}{Nummer}
Modul eins & 2 & 3 \\
Modul zwei & 5 & 6 \\
Modul drei & 8 & 9 \\
Modul vier & 2 & 3 \\
Modul fünf & 5 & 6 \\
Modul sechs & 8 & 9 \\
\end{tabulargreen}

\vspace{5mm}

\begin{tabulargreen}{Name}{Zahl}
Modul eins & 3 \\
Modul zwei & 4 \\
Modul drei & 7 \\
\end{tabulargreen}

\end{document}

The tables still look like this:

Where does the "M" come from and how can I get rid of it?

Greetings and thanks a lot!

S.Millie

Answer 1

It's easier if you have only one argument, the header with the cells separated by the usual &.

\documentclass{article} 
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[sfdefault]{AlegreyaSans}
\usepackage[table,x11names,dvipsnames,table]{xcolor}
\usepackage{xparse}

\definecolor{mygreen}{RGB}{126,169,105}
\definecolor{myblue}{RGB}{9,28,87}

\ExplSyntaxOn

\seq_new:N \l_millie_tabgreen_head_in_seq
\seq_new:N \l_millie_tabgreen_head_out_seq

\NewDocumentEnvironment{tabulargreen}{m}
 {
  \seq_set_split:Nnn \l_millie_tabgreen_head_in_seq { & } { #1 }
  \seq_set_map:NNn
   \l_millie_tabgreen_head_out_seq
   \l_millie_tabgreen_head_in_seq
   { \millie_tabgreen_head:n { ##1 } }
  \rowcolors{1}{mygreen!20}{mygreen!10}
  \begin{tabular}
   {
    l
    *{ \int_eval:n { \seq_count:N \l_millie_tabgreen_head_in_seq - 2 } } { c }
    r
   }
   \rowcolor{mygreen}
   \seq_use:Nn \l_millie_tabgreen_head_out_seq { & } \\
 }
 {
  \end{tabular}
 }
\cs_new_protected:Nn \millie_tabgreen_head:n
 {
  \textcolor{white}{\bfseries #1}
 }
\ExplSyntaxOff

\begin{document}

\begin{tabulargreen}{Name & Zahl & Nummer}
Modul eins & 2 & 3 \\
Modul zwei & 5 & 6 \\
Modul drei & 8 & 9 \\
Modul vier & 2 & 3 \\
Modul fünf & 5 & 6 \\
Modul sechs & 8 & 9 \\
\end{tabulargreen}

\vspace{5mm}

\begin{tabulargreen}{Name & Zahl}
Modul eins & 3 \\
Modul zwei & 4 \\
Modul drei & 7 \\
\end{tabulargreen}

\end{document}

The idea is to count the number of headers, subtract 2 and make a suitable preamble l c … c r; the headers are massaged to add the requested formatting and then the table is built.

Answer 2

As David says you still need to pass in three parameters based on how you have defined the tabulargreen environment:

\begin{tabulargreen}{Name}{Zahl}{}

As per the comments the code has beed modified to allow for 4 parameters (where the first two are mandatory and the last two are optional). So, not you need to invoke this as

\begin{tabulargreen}{Name}{Zahl}{}{}

Then, in the tabulargreen option you need to check if the optional parameters are empty and not define a column heading if they are. I used the ifmtarg package to do that but any other method to detect an empty option (such as using xparse) will do.

This technique can be extended to a maximum of nine paramters. Beyond that you need to do additional processing (see References).

Notes:

• You were missing a trailing: \end{tabular}% -- I have added this to the code below. This removes extra horizontal spacing following the tabular (which won't show anything different in this MWE, but if you an \fbox{} around the usage of tabulargreen you can see the difference.

References:

• How to check if a macro value is empty or will not create text with plain TeX conditionals?
• How to make more-than-9-argument-commands work with tabular?.

Code:

\documentclass{article} 
%\usepackage[utf8]{inputenc}
%\usepackage[T1]{fontenc}
%\usepackage[sfdefault]{AlegreyaSans}
\RequirePackage{booktabs}
\usepackage[table,x11names,dvipsnames,table]{xcolor}
\usepackage{tabularx}
\usepackage{ifmtarg}
\makeatletter%
    \newcommand{\IfIsEmptyArg}[3]{@ifmtarg{#1}{#2}{#3}}%
\makeatother%
\definecolor{mygreen}{RGB}{126,169,105}
\definecolor{myblue}{RGB}{9,28,87}
\begin{document}
\newenvironment{tabulargreen}[4]% <-- Note: 4 paramaters
  { 
  %\renewcommand{\tempcaption}{#3}
  \rowcolors{1}{mygreen!20}{mygreen!10}
   \begin{tabular}{lcrr}
   \rowcolor{mygreen}
   \textcolor{white}{\bfseries #1} 
       & \textcolor{white}{\bfseries #2}
       \IfIsEmptyArg{#3}{}{& \textcolor{white}{\bfseries #3}}
       \IfIsEmptyArg{#4}{}{& \textcolor{white}{\bfseries #4}} 
       \
   }
  {
   %\caption{\tempcaption}
   \end{tabular}% <---- Note trailing %
   }
\begin{tabulargreen}{Name}{Zahl}{Nummer}{}% <-- Note: 4 paramaters
Modul eins & 2 & 3 \
Modul zwei & 5 & 6 \
Modul drei & 8 & 9 \
Modul vier & 2 & 3 \
Modul funf & 5 & 6 \
Modul sechs & 8 & 9 \
\end{tabulargreen}
\par\medskip
\begin{tabulargreen}{Name}{Zahl}{}{}% % <-- Note: 4 paramaters
Modul eins & 3 \
Modul zwei & 4 \
Modul drei & 7 \
\end{tabulargreen}
\par\medskip
\begin{tabulargreen}{A}{B}{C}{D}% % <-- Note: 4 paramaters
1 & 2 & 3 & 4 \
a & b & c & d \
\end{tabulargreen}
\end{document}