Need help for macro to split a string and put the substrings into temp variables

Question

I have something like this:

\documentclass{article}

\newcommand*\tableData[2]{string1,string2,string3}{string4}

\newcommand*{\String1}[1]{#1}
\newcommand*{\String2}[1]{#1}
\newcommand*{\String3}[1]{#1}
\newcommand*{\String4}[1]{#1}

\begin{document}

 \String1 
 ..
 \String4

\end{document}

So, i have two parameters, but i want to split the commaseparated strings in the first parameter and put it in the variables. How to do this with build-in-command or is it a better way to work with a package?

I found this already, but i want to put the different strings in different variables, not in \fbox or something else...

Answer 1

I suggest the clist facilities by expl3 and a \GetString{number} macro which fetches the relevant string with number number instead a bunch of \StringOne etc. routines

Edit: Please note that the list container \g_samhoff_string_clist is cleared each time \tableData is used.

\documentclass{article}


\usepackage{xparse}


\ExplSyntaxOn
\clist_new:N \g_samhoff_string_clist
\NewDocumentCommand{\tableData}{mm}{
  \clist_clear:N \g_samhoff_string_clist % Clearing the list
  \clist_set:Nn{\g_samhoff_string_clist}{#1}
  \clist_put_right:Nn{\g_samhoff_string_clist}{#2}
}

\NewDocumentCommand{\GetString}{m}{
  \clist_item:Nn{\g_samhoff_string_clist}{#1}
}

\ExplSyntaxOff


\begin{document}

\tableData{one, two, three}{four}

Now the data:

\GetString{1}

\GetString{2}

\GetString{3}

\GetString{4}

\end{document}

Explanation:

• \tableData is defined to be a macro with two mandatory arguments, therefore {mm}

• The first argument is supposed to have the comma-separated-value list.

• \clist_new:N \g_samhoff_string_clist defines a new csv - list variable globally with name g_samhoff_string_clist. (\g stands for global)
• At the begin of \tableData, clear the list: \clist_clear:N
• Now store the first parameter (the clist!) with \clist_set:Nn
• Append the 2nd parameter to right side of \g_samhoff_string_clist} with \clist_put_right:Nn

With \clist_item{\g_samhoff_string_clist}{2} for example it's possible to fetch the 2nd item in the list.

\ExplSyntaxOn and \ExplSyntaxOff are necessary to make the new macro names possible (and other stuff)