# [OS X TeX] using variables in text via references or labels

Gert van Oss gertmt at mac.com
Mon Mar 30 23:35:53 CEST 2009

Thank you both! It took me some minutes to find out how to install
some missing parts of Latex: datatool, xfor.

And then I got the example to work, this is exactly what works for me!
I didn't know how to look for this solution as I didn't know something
like this existed.

I'm using very large tables in my documents but I'll just create a
summary-table with the specific numbers that I'll want to mention in
my text so efficiency is not a problem. It will anyhow always be
better then scanning my screen for a number I might have forgotten to
append.

Thanks again,
Gert

On 30 mrt 2009, at 23:08, Alan Munn wrote:

> At 8:31 PM +0200 3/30/09, Gert van Oss wrote:
>> dear all,
>>
>> I've had some problem making up a clear subject line and stil am in
>> doubt whether I've succeded. What I'm trying to achieve is the
>> following.
>>
>> My documents have often various tables and charts embedded via the
>>
>>   \input{table_file}
>>
>> command.
>>
>> While explaining my tables/charts I'm mentioning actual numbers (as
>> listed in the tables) in my text. Is it somehow possible to create
>> a list of numbers in my latex document and have them called via a
>> reference in my text? This would enable me to run a somewhat
>> related scenario in my numbers and udpate both my tables with
>> numbers and have all numbers changed in the text as well.
>>
>> I was thinking this should be possible while using \labels, \ref
>> but for the moment can't stretch my mind to find a solution.
>
> As Ross mentioned, there's no good way to refer to the elements of a
> table in LaTeX format. For tabular data from external sources I use
> datatool.sty and keep the data in Excel or OpenOffice csv files.
> The following is a small proof of concept that would allow you to
> make reference to individual cells in a table stored in a csv file
> and created using datatool.
>
> For figures, I don't see a solution, but if the figures have an
> associated table, the same solution could be used (even if the table
> for the figure isn't displayed in the document.)
>
> Alan
>
> ---cut here---
>
> % Proof of concept for arbitrary reference to table cells using
> datatool.
> % This assumes that your table's first column contains row numbers
> (used
> % for indexing the rows).  If tables are very large, this could get
> quite
> % inefficient, since the \getrow command rereads the database each
> time.
> % For the current example, the database t1.csv consists of the
> following:
> % Cut and past this and save as t1.csv (without the % and leading
> spaces).
> % ---t1.csv---
> % Index,A,B,C,D
> % 1,10,20,40,80
> % 2,8,16,32,64
> % 3,1,2,4,8
> %---t1.csv
>
> \documentclass{article}
> \usepackage{datatool}
>
> % Define a command which takes a database name and a rownumber as
> arguments
> % and returns the elements of that row as separate commands. This is
> to be
> % used for reference to particular cells.
> %
> \newcommand{\getrow}[2]{%
> \DTLforeach*[\DTLiseq{\myindex}{#2}]{#1}{%
> \myindex=Index,\myindex=Index,\tableA=A,\tableB=B,\tableC=C,
> \tableD=D}}
>
>
> \begin{document}
>
> \begin{table}
> \centering
> \begin{tabular}{llll}
> \DTLforeach{t1}{%
> \myindex=Index,\tableA=A,\tableB=B,\tableC=C,\tableD=D}{%
> \\
> \tableA & \tableB & \tableC & \tableD}
>
> \end{tabular}
> \caption{Some numbers}
> \end{table}
> As we can see from the table the element in row 1 column 4 is
> \getrow{t1}{1}\tableD, is a small number.
> \end{document}
> --
> Alan Munn						amunn at msu.edu
> Department of Linguistics
> and Germanic, Slavic, Asian and African Languages		Tel. 	517-355-7491
> Michigan State University, East Lansing MI 48824 USA	Fax	517-432-2736
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