# Custom list labels in ConTeXt

I have just started learning ConTeXt and I have to say that I am pretty amazed by how intuitive it is to use. But I can't find a way yet to achieve automatically a list with the following labels.

C.1
C.2
C.3
.
.
.

What I have come up with so far is with the use of \sym:

\starttext
\startitemize[packed]
\sym{C.1} Three coins are tossed. In how many ways can at least 2 heads turn up?
\sym{C.2} If $\log_x 8^{1/2}=3/4$, what is $x$?
\sym{C.3} If $x:y=10:21$ and $y:z=28:9$, what is $x:y:z$?
\stopitemize
\stoptext

In LaTeX, with the enumitem package, it is easy to achieve this with the following minimal code:

\documentclass{article}
\usepackage{enumitem}
\begin{document}
\begin{enumerate}[label={C.\arabic*}]
\item ...
\end{enumerate}
\end{document}

Is there a way that I can automate the list in ConTeXt? I tried some of the ConTeXt manuals but all I have seen up to now are just the predefined lists. I also tried looking for a duplicate in this site using the [context] tag but I have been unsuccessful so far.

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Nice to see yet another brave ConTeXt user! ConTeXt is really a great system, much better than LaTeX in many respects (but having its limitations, too). Did you see this: wiki.contextgarden.net/User-Defined_Enumerations ? –  mbork Feb 9 '13 at 2:30
@mbork Thanks for the link. I am really getting out of my comfort zone here. But I am afraid using the strategy in the link, I have to manually specify the labels myself. Is there an easier way to do this? –  hpesoj626 Feb 9 '13 at 3:19

You can use the command \setupitemgroup to configure how the itemize lists are being displayed. See ConTeXt wiki - setupitemgroup for more information.

\setupitemgroup
[itemize]
[packed, n]

\setupitemgroup
[itemize]
[distance=2ex,
left=C.,
stopper=]

\starttext
\startitemize
\startitem Three coins are tossed.                 \stopitem
\startitem If \math{\log_x 8^{1/2}=3/4}            \stopitem
\startitem If \math{x:y=10:21} and \math{y:z=28:9} \stopitem
\stopitemize
\stoptext

The n setting changes the bullet to a number, the left key controls what is printed at the left of the enumeration and removing the stopper gets rid of the dot which is used by default for numbered items.

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Thanks Marco! I did see \setitemgroup and was already doing some experiments with it. I saw the left option but had no I idea what it does until I saw it in your answer. In the ConTeXt wiki for instance, it was just described as text. Thanks again! –  hpesoj626 Feb 9 '13 at 12:33
If you want to do this for a one off list, you can also use \startitemize[n][left=C.] –  Aditya Feb 9 '13 at 13:31
@Aditya That simple? Okay, yeah. it was a one off list. Thanks. That was really helpful. –  hpesoj626 Feb 9 '13 at 13:39