How can I have references to several counters in a formatted way with \ref{}?

Question

I have two counters in my document, counterA and counterB.

I would like the references \ref{} in my document to be printed as 1.a) or 2., etc. where the digit refers to counterA and the letter to counterB.

Is it possible? How can I do it?

\documentclass{article}
\begin{document}

\newcounter{counterA} 
\setcounter{counterA}{0}

\newcounter{counterB}
\setcounter{counterB}{0}


\refstepcounter{counterA}
\refstepcounter{counterB}
\label{First_Label}

I get: \ref{Second_Label}. I would like \textbf{2.}\,b)

Vestibulum lectus metus, tincidunt at fermentum non, pellentesque at lorem. Vivamus nisl sem, tempor ac mi et, elementum feugiat justo. Pellentesque tristique consequat molestie.


\bigskip
\refstepcounter{counterA}
\refstepcounter{counterB}
\label{Second_Label}

I get: \ref{First_Label}. I would like \textbf{1.}\,a)

Morbi nec nibh nulla. Cras posuere erat vitae lacus convallis, ut consequat urna dignissim. 
\end{document}

Answer 1

You can use the following command:

\renewcommand{\thecounterB}{\textbf{\thecounterA}.\alph{counterB})}

Here's a complete MWE:

% arara: pdflatex
\documentclass{article}

\newcounter{counterA} 
\setcounter{counterA}{0}

\newcounter{counterB}
\setcounter{counterB}{0}

\renewcommand{\thecounterB}{\textbf{\thecounterA}.\alph{counterB})}
\begin{document}

\refstepcounter{counterA}
\refstepcounter{counterB}
\label{First_Label}

I get: \ref{Second_Label}. I would like \textbf{2.}\,b)

Vestibulum lectus metus, tincidunt at fermentum non, pellentesque at lorem. Vivamus nisl sem, tempor ac mi et, elementum feugiat justo. Pellentesque tristique consequat molestie.


\bigskip
\refstepcounter{counterA}
\refstepcounter{counterB}
\label{Second_Label}

I get: \ref{First_Label}. I would like \textbf{1.}\,a)

Morbi nec nibh nulla. Cras posuere erat vitae lacus convallis, ut consequat urna dignissim. 
\end{document}

Answer 2

Every time one creates a counter variable named, say, counterB, with a \newcounter instruction, LaTeX sets up a macro called \p@counterB that can be used to "prefix" some other information to the label for the sake of creating a cross-reference. I.e., you could type

\makeatletter
\renewcommand\p@counterB{\thecounterA.}
\makeatother

to prefix LaTeX's representation of the current value of counterA plus a . to LaTeX's representation of the value of counterB.

A full MWE:

\documentclass{article}
\newcounter{counterA}
\newcounter{counterB}
\renewcommand\thecounterA{\arabic{counterA}} % arabic numbering
\renewcommand\thecounterB{\alph{counterB})}  % alphabetic numbering
\makeatletter
\renewcommand\p@counterB{\thecounterA.}
\makeatother
\begin{document}
% need to increment the counters via \refstepcounter
\refstepcounter{counterA} \label{refA}
\refstepcounter{counterB} \label{refB}
Here's a cross-reference to item \ref{refB}.
\end{document}