# Reference sections or chapters without labeling?

Is it possible to reference chapters and sections of a document without manually labelling every section and subsection ?

I have about 8 chapters and dozens of sections/subsections indented inside of them, labelling each single section is pretty tedious.

Is there a faster, more convenient way ?

• I believe that NO. – Sigur Apr 12 '13 at 1:17
• Using emacs with AucTeX might be a "work around": using the AucTeX system to input sections -- C-c C-s and you can label each section, just by hitting the Enter key. – kan Apr 12 '13 at 1:25
• You don't have to label each one; only the ones you want to reference. Did you know that? – Werner Apr 12 '13 at 2:46
• "Is there a faster, more convenient way?" No. – egreg Apr 12 '13 at 7:41

This can be done, but it could be risky; in the following example, the first word of each chapter or section is taken to automatically build the label with each invokation of \chapter or \section; titlesec with its explicit option was used to grab the title; using xstring, the first word is extracted:

\documentclass[10pt]{book}
\usepackage[explicit]{titlesec}
\usepackage{xstring}

\titleformat{\chapter}[display]
{\normalfont\huge\bfseries}{\chaptertitlename\ \thechapter}{20pt}{\Huge\StrBefore{#1}{ }[\mlabel]#1\label{\mlabel}}
\titleformat{\section}
{\normalfont\Large\bfseries}{\thesection}{1em}{\StrBefore{#1}{ }[\mlabel]#1\label{\mlabel}}

\begin{document}

Some references to chapters: \ref{Some} and \ref{Other} and some references to sections: \ref{A} and \ref{Another}
\chapter{Some Chapter}
\section{A Test Section}
\chapter{Other Chapter}
\section{Another Test Section}

\end{document}


If two sectional units have the same initial word in their titles, this will fail, but you could then select a different string to build the labels.

In my initial solution I assumed that the titles contain at least one blank space, but one could use another string; for example (as in nicolai.rostov's answer) the whole name of the sectional unit. In this case, the xstring package is not needed anymore and one could simply say

\documentclass[10pt]{book}
\usepackage[explicit]{titlesec}

\titleformat{\chapter}[display]
{\normalfont\huge\bfseries}{\chaptertitlename\ \thechapter}{20pt}{\Huge#1\label{#1}}
\titleformat{\section}
{\normalfont\Large\bfseries}{\thesection}{1em}{#1\label{#1}}

\begin{document}

Some references to chapters: \ref{Some Chapter} and \ref{Other Chapter} and some references to sections: \ref{A Test Section} and \ref{Another Test Section}
\chapter{Some Chapter}
\section{A Test Section}
\chapter{Other Chapter}
\section{Another Test Section}

\end{document}


My examples only show the mechanism for chapters and sections, but it can be easily extended to other sectional units.

• I'm glad you found my idea useful. Maybe you should vote my answer up? ;) – n.r. Apr 12 '13 at 4:25
• @nicolai.rostov I credited you in my answer. – Gonzalo Medina Apr 12 '13 at 4:49

You may use the full title of chapters or sections as labels, and refer back to them by means of their own titles.

\documentclass{book}

\let\origchapter=\chapter
\let\origsection=\section

\renewcommand\chapter[1]{\origchapter{#1}\label{#1}}
\renewcommand\section[1]{\origsection{#1}\label{#1}}

\begin{document}

\chapter{My first chapter}

\section{My first section}

I said in section~\ref{My first section} at the
beginning of chapter~\ref{My first chapter} that

\end{document}

• With your definitions you loose the optional argument. – Gonzalo Medina Apr 12 '13 at 3:56
• @GonzaloMedina So how can he fix it? – PHPst Oct 28 '13 at 18:01

You can automate the label creation process. A very basic perl script can do it. The perl script has to globe all your .tex files and run a substitution regex on them, one by one. Here is an example of the regex you should use:

my $input_str = do{ local$/; <> };
$input_str =~ s/(\\section{(.*?)}(?!\s*\\label))/$1\n\\label{sec:$2}/mg;$input_str =~ s/(\\chapter{(.*?)}(?!\s*\\label))/$1\n\\label{chap:$2}/mg;
print \$input_str;


These two regex will simply look for each \chapter{Chapter Title} and \section{Section Name} in your tex code . If they have a label defined after that, the script will ignore them. If not, the script will add a label statement for them on a new line that reads \label{chap:Chapter Title} and \label{sec:Section Name}. You can create this perl script and run it whenever you create new sectoins/chapters.

DISCLAMER: I am not responsible for any loss of data you may encounter when running regex's over your .tex files. Although I tested the above regex's, I intentionally did not include the code for a complete perl script, so as to avoid such risk. You can still view my perl code in action if you cut & paste it in a script, run it on a .tex file. It will work and print the results on screen without modifying your file. Make sure to write your own Perl script and test it on dummy .tex files. Also, make sure to always take a copy of your work before running such scripts on it.