TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. It only takes a minute to sign up.
Sign up to join this community
I would like to compile a snippet of code using a random case distinction. How can I implement that?
No-LaTeX pseudocode:
x = rand(1,4) // random number between 1 and 4
if( x == 1 )
Let us talk about apples!
else if( x == 2 )
Let us talk about pears!
else if( x == 3 )
Let us talk about plums!
else
Let us talk about cherries!
What is the best way this can be implemented? I would like to use it within math environments as well.
You can make a command that outputs a random item from a list.
The items must be braced if they contain more than one token.
There are two versions: the first defines a command (suitable for long lists), the second can be used inline.
\documentclass{article}
\usepackage{xparse}
\ExplSyntaxOn
\NewDocumentCommand{\makerandomchoice}{mm}
{
\shuhalo_random_choice_make:Nn #1 { #2 }
}
\NewExpandableDocumentCommand{\randomchoice}{m}
{
\shuhalo_random_choice:n { #1 }
}
\cs_new_protected:Nn \shuhalo_random_choice_make:Nn
{
\cs_new:Npn #1
{
\shuhalo_random_choice:n { #2 }
}
}
\cs_new:Nn \shuhalo_random_choice:n
{
\tl_item:nn { #1 } { \int_rand:nn { 1 } { \tl_count:n { #1 } } }
}
\ExplSyntaxOff
\makerandomchoice{\talk}{
{Let us talk about apples!}
{Let us talk about pears!}
{Let us talk about plums!}
{Let us talk about cherries!}
}
\makerandomchoice{\letter}{ABCDEFGHIJKLMNOPQRSTUVWXYZ}
\begin{document}
\talk
\talk
\talk
\talk
\talk
\letter\letter\letter\letter\letter\letter\letter\letter
\letter\letter\letter\letter\letter\letter\letter\letter
\randomchoice{{Pear}{Apple}{Plum}{Cherry}}
\randomchoice{{Pear}{Apple}{Plum}{Cherry}}
\randomchoice{{Pear}{Apple}{Plum}{Cherry}}
\randomchoice{{Pear}{Apple}{Plum}{Cherry}}
\end{document}
Spaces between items are ignored.
If you know R and knitr, this can be achieved with some very similar to your pseudocode:
\documentclass{article}
\begin{document}
<<fruit-roulette,echo=F,cache=FALSE>>=
x <- sample(1:4, 1)
talk <- if( x == 1 ) {"apples"} else {
if( x == 2 ) {"pears"} else {
if( x == 3 ) {"plums"} else {
if( x == 4 ) {"cherries"}}}}
@
Because $x=\Sexpr{x}$, let us talk about \Sexpr{talk}!
\end{document}
In each compilation the LaTeX text could change, being one possible result:
As you see here, the \Sexpr{} can be use in math and text modes, but take into account that the R output will be formatted according to LaTeX rules (e.g., being the foo R object "big apples", \Sexpr{foo} or $\mbox{\Sexpr{foo}}$ will produce just "big apples", but \Sexpr{talk} will produce "bigapples".
random.texfile for generating and using random numbers.