Andrea Giovacchini
Andrea Giovacchini

Reputation: 5187

Is there any way I can define a variable in LaTeX?

In LaTeX, how can I define a string variable whose content is used instead of the variable in the compiled PDF?

Let's say I'm writing a tech doc on a software and I want to define the package name in the preamble or somewhere so that if its name changes, I don't have to replace it in a lot of places but only in one place.

Upvotes: 474

Views: 471583

Answers (5)

second
second

Reputation: 28637

add the following to you preamble:

\newcommand{\newCommandName}{text to insert}

Then you can just use \newCommandName{} in the text

For more info on \newcommand, see e.g. wikibooks

Example:

\documentclass{article}
\newcommand\x{30}
\begin{document}
\x
\end{document}

Output:

30

Upvotes: 530

John Burt
John Burt

Reputation: 136

I think you probably want to use a token list for this purpose: to set up the token list \newtoks\packagename to assign the name: \packagename={New Name for the package} to put the name into your output: \the\packagename.

Upvotes: 1

user1125069
user1125069

Reputation: 389

If you want to use \newcommand, you can also include \usepackage{xspace} and define command by \newcommand{\newCommandName}{text to insert\xspace}. This can allow you to just use \newCommandName rather than \newCommandName{}.

For more detail, http://www.math.tamu.edu/~harold.boas/courses/math696/why-macros.html

Upvotes: 28

plaes
plaes

Reputation: 32716

Use \def command:

\def \variable {Something that's better to use as a variable}

Be aware that \def overrides preexisting macros without any warnings and therefore can cause various subtle errors. To overcome this either use namespaced variables like my_var or fall back to \newcommand, \renewcommand commands instead.

Upvotes: 205

For variables describing distances, you would use \newlength (and manipulate the values with \setlength, \addlength, \settoheight, \settolength and \settodepth).

Similarly you have access to \newcounter for things like section and figure numbers which should increment throughout the document. I've used this one in the past to provide code samples that were numbered separatly of other figures...

Also of note is \makebox which allows you to store a bit of laid-out document for later re-use (and for use with \settolength...).

Upvotes: 46

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