LaTeX/Counters

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Counter manipulationEdit

In LaTeX it is fairly easy to create new counters and even counters that reset automatically when another counter is increased (think subsection in a section for example). With the command

\newcounter{NameOfTheNewCounter}

you create a new counter that is automatically set to zero. If you want the counter to be reset to zero every time another counter is increased, use:

\newcounter{NameOfTheNewCounter}[NameOfTheOtherCounter]

To increase the counter, either use

\stepcounter{NameOfTheNewCounter}

or

\refstepcounter{NameOfTheNewCounter} % used for labels and cross referencing

or

\addtocounter{NameOfTheNewCounter}{number}

here the number can also be negative. For automatic resetting you need to use \stepcounter.

To set the counter value explicitly, use

\setcounter{NameOfTheNewCounter}{number}

Counter accessEdit

There are several ways to get access to a counter.

  • \theNameOfTheNewCounter will print the formatted string related to the counter (note the "the" before the actual name of the counter).
  • \value{NameOfTheNewCounter} will return the counter value which can be used by other counters or for calculations. It is not a formatted string, so it cannot be used in text.
  • \arabic{NameOfTheNewCounter} will print the formatted counter using arabic numbers.

Note that \arabic{NameOfTheNewCounter} may be used as a value too, but not the others.

Strangely enough, LaTeX counters are not introduced by a backslash in any case, even with the \the command. plainTeX equivalents \count and \newcounter\mycounter do abide by the backslash rule.

Counter styleEdit

Each counter also has a default format that dictates how it is displayed whenever LaTeX needs to print it. Such formats are specified using internal LaTeX commands:

Command Example
\arabic 1, 2, 3 ...
\alph a, b, c ...
\Alph A, B, C ...
\roman i, ii, iii ...
\Roman I, II, III ...
\fnsymbol Aimed at footnotes; prints a sequence of symbols.

LaTeX default countersEdit

  • part
  • chapter
  • section
  • subsection
  • subsubsection
  • paragraph
  • subparagraph
  • page
  • figure
  • table
  • footnote
  • mpfootnote

For the enumerate environment:

  • enumi
  • enumii
  • enumiii
  • enumiv

For the eqnarray environment:

  • equation

Book with parts, sections, but no chaptersEdit

Here follows an example where we want to use parts and sections, but no chapters in the book class :

\renewcommand{\thesection}{\thepart .\arabic{section}}

\part{My Part}                                                                
\section{My Section}
\subsection{My Subsection}

Custom enumerateEdit

See the List Structures chapter.

Custom sectioningEdit

Here is an example for recreating something similar to a section and subsection counter that already exist in LaTeX:

\newcounter{mysection}
\newcounter{mysubsection}[mysection]
\addtocounter{mysection}{2} % set them to some other numbers than 0
\addtocounter{mysubsection}{10} % same
%
\arabic{mysection}.\arabic{mysubsection}
Blah blah

\stepcounter{mysection}
\arabic{mysection}.\arabic{mysubsection}
Blah blah

\stepcounter{mysubsection}
\arabic{mysection}.\arabic{mysubsection}
Blah blah

\addtocounter{mysubsection}{25}
\arabic{mysection}.\arabic{mysubsection}
Blah blah and more blah blah


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