[Tex/LaTex] How to reference the current (sub)section number

countersmacrosnumberingsectioning

I want to create a macro that dynamically returns the current chapter, section, subsection (etc.) I'm in. I've created a macro called \getCurrentSectionNumber that does this, but it lacks the ability to figure out how many levels deep it is and shorten/lengthen the result accordingly. This macro should essentially return the full numbering text of the most recent subsection, section, or chapter where it was invoked.

This macro should produce the following text at the given places.

A: "1"
B: "1.1"
C: "1.1.1"
D: "1.1.2"
E: "1.2"
F: "1.2.1"
G: "1.2.2"

Note that at A, it prints "1.??" because there is no section defined at that point. Locations C, D, F, and G all omit the subsection.

Example:

\documentclass{report}
\usepackage{etoolbox}


\newcommand\getcurrentref[1]{%
 \ifnumequal{\value{#1}}{0}
  {??}
  {\the\value{#1}}%
} 
\newcommand{\getCurrentSectionNumber}{\getcurrentref{chapter}.\getcurrentref{section}}


\begin{document}

\chapter{My Example}
A: Current number is \getCurrentSectionNumber

\section{Section One-point-One}
    B: Current number is \getCurrentSectionNumber
    \subsection{subsection one-point-one-point-one}
        C: Current number is \getCurrentSectionNumber
    \subsection{subsection one-point-one-point-two}
        D: Current number is \getCurrentSectionNumber
\section{Section Two}
    E: Current number is \getCurrentSectionNumber
    \subsection{subsection one-point-two-point-one}
        F: Current number is \getCurrentSectionNumber
    \subsection{subsection one-point-two-point-two}
        G: Current number is \getCurrentSectionNumber

\end{document}

Example's Output:

output of the example code given above

Any help would be appreciated. Thanks!

Best Answer

You mean something like this? We simply use the fact that the "lower" section number is always 0 when that sectioning level is not used at the moment.

\documentclass{report}

\makeatletter
\newcommand{\getCurrentSectionNumber}{%
  \ifnum\c@section=0 %
  \thechapter
  \else
  \ifnum\c@subsection=0 %
  \thesection
  \else
  \ifnum\c@subsubsection=0 %
  \thesubsection
  \else
  \thesubsubsection
  \fi
  \fi
  \fi
}

\makeatother

\begin{document}

\chapter{My Example}
A: Current number is \getCurrentSectionNumber %1

\section{Section One-point-One}
    B: Current number is \getCurrentSectionNumber % 1.1
    \subsection{subsection one-point-one-point-one}
        C: Current number is \getCurrentSectionNumber % 1.1.1
    \subsection{subsection one-point-one-point-two}
        D: Current number is \getCurrentSectionNumber % 1.1.2
\section{Section Two}
    E: Current number is \getCurrentSectionNumber % 1.2
    \subsection{subsection one-point-two-point-one}
        F: Current number is \getCurrentSectionNumber % 1.2.1
    \subsection{subsection one-point-two-point-two}
        G: Current number is \getCurrentSectionNumber % 1.2.2

\end{document}

Related Solutions

[Tex/LaTex] Theorem/Definition/Lemma problem — Numbering

Similar to the solution at this question and section 3 of the amsthm documentation:

enter image description here

\documentclass[11pt,a4paper]{report}
\usepackage{amsthm}

\theoremstyle{plain}
\newtheorem{thm}{Theorem}[chapter] % reset theorem numbering for each chapter

\theoremstyle{definition}
\newtheorem{defn}[thm]{Definition} % definition numbers are dependent on theorem numbers
\newtheorem{exmp}[thm]{Example} % same for example numbers

\newcommand{\chaptercontent}{
\section{Basics}
\begin{defn}Here is a new definition.\end{defn}
\begin{thm}Here is a new theorem.\end{thm}
\begin{thm}Here is a new theorem.\end{thm}
\begin{exmp}Here is a good example.\end{exmp}
\subsection{Some tips}
\begin{defn}Here is a new definition.\end{defn}
\section{Advanced stuff}
\begin{defn}Here is a new definition.\end{defn}
\subsection{Warnings}
\begin{defn}Here is a new definition.\end{defn}
}

\begin{document}
\tableofcontents
\part{Addition and Subtraction}
\chapter{Addition} \chaptercontent
\chapter{Subtraction} \chaptercontent
\part{Multiplication and Division}
\chapter{Multiplication} \chaptercontent
\chapter{Division} \chaptercontent
\end{document}

[Tex/LaTex] Problems with theorem/definition/statement numbering

With package remreset the reset dependencies can be removed. For example, if counter theorem is reset if counter subsection is incremented, then

\usepackage{remreset}
\makeatletter
\@removefromreset{theorem}{subsection}
\makeatother

the resetting is removed.

The other way \@addtoreset does not need a package. For example, if counter theorem should be reset if counter section is incremented:

\makeatletter
\@addtoreset{theorem}{section}
\makeatother

The appearance of the counter is controlled by \the<counter>. For example, in the latter case it could be redefined to:

\renewcommand*{\thetheorem}{\thesection.\arabic{theorem}}

Macro \numberwithin of package amsmath performs both steps, adding reset dependency and renaming \the<counter>:

\usepackage{amsmath}
\numberwithin{theorem}{section}

I hope, you get the idea. A minimal working example is missing. Thus it is not clear to me, what you are doing. Especially the numbering inside subsections is quite unusual. Perhaps it is wise to check the preamble if this is not intended.

Also it looks even more odd, if the numbering occurs inside subsections without the section number, but with subsection number. The numbers are not unique, thus it is not clear which theorems are meant if only the reference is given.

I would keep the numbering scheme easy and understandable:

Plain numbers without resetting at all: Theorem 1, Theorem 2, …

1. First chapter
Theorem 1
Theorem 2
2. Second chapter
Theorem 3
Theorem 4

Numbering in a large entity like chapter or section, if the class does not provide chapters:
```
1. First chapter  
Theorem 1.1
Theorem 1.2
2. Second chapter
Theorem 2.1
Theorem 2.2
```

Then the reader has a chance to understand the numbering without going in deciphering mode.