Latex foreach in tabular environment

Question

I'm trying to use the tikz package's foreach command in a tabular environment. I know that it is not really suited for doing this, but how would I be able to make the following command work (I think, it is obvious what it should do, and I know that there are some difficulties regarding the textbf command as well):

\newcommand{\myTable}[1]{
    \begin{tabular}{p{0.35\textwidth}|p{0.65\textwidth}}
        \hline
        Headline 1 & Headline 2 \\
        \foreach \lhs/\rhs in {#1} {
            \textbf{\lhs} & \rhs \\
        }
        \hline
    \end{tabular}
}

MWE:

\documentclass{article}
\usepackage{tikz}

\newcommand{\myTable}[1]{
    \begin{tabular}{p{0.35\textwidth}|p{0.65\textwidth}}
        \hline
        Headline 1 & Headline 2 \\
        \foreach \lhs/\rhs in {#1} {
            \textbf{\lhs} & \rhs \\
        }
        \hline
    \end{tabular}
}

\begin{document}
\myTable{{Title 1}/{Description 1}, {Title 2}/{Description 2}}
\end{document}

Answer 1

The following slightly painful code does this using \foreach from tikz:

\documentclass{article}
\usepackage{etoolbox}
\usepackage{tikz}
\makeatletter
\newcommand{\myTable}[1]{%
    \def\tabledata{}% reset \tabledata
    \foreach \lhs/\rhs in {#1} {% build table data from #1  
        \protected@xappto\tabledata{\textbf{\lhs} & \rhs \\}
    }%
    \begin{tabular}{p{0.35\textwidth}|p{0.65\textwidth}}
        \hline
        Headline 1 & Headline 2 \\ \hline
        \tabledata \hline
    \end{tabular}
}
\makeatother

\begin{document}
   \myTable{{Title 1}/{Description 1}, {Title 2}/{Description 2}}
\end{document}

The trick is that you need to construct the table data first and then put it inside the tabular environment. Expanding \\ causes issues as well.

A more straightforward approach is to use \docsvlist from etoolbox:

\documentclass{article}
\usepackage{etoolbox}
\def\addtablerow#1/#2!{\textbf{#1} & #2\\}
\newcommand{\myTable}[1]{
    \renewcommand*\do[1]{\addtablerow##1!}
    \begin{tabular}{p{0.35\textwidth}|p{0.65\textwidth}}
        \hline
        Headline 1 & Headline 2 \\ \hline
        \docsvlist{#1} \hline
    \end{tabular}
}

\begin{document}
    \myTable{Title 1/Description 1, Title 2/Description 2}
\end{document}

The \docsvlist command applies the (current version of) \do to each element in the comma separated list. In turn, \do calls \addtablerow, which expects two arguments, which are delimited by / and !.

In both cases you end up with:

Btw, in both cases you can drop many of the braces - as shown in the second example.