dyntext.dotex

<<dd_version: 1>>

\documentclass[12pt]{article}
\usepackage{graphicsx}
\begin{document}

\section{Using Stata dynamic tags in a text file with the \texttt{dyntext} command}

Let us consider an example where we study the \texttt{mpg} and \texttt{weight} variables in
\texttt{auto.dta}. In our examples below, we will first write the commands so that
they will be displayed in our output text file.  Then, we will write the
commands so that Stata will process the Stata dynamic tags, displaying the
results of the Stata commands in the output text file.

We first use the \texttt{sysuse} command to load the dataset and then describe
the data using the \texttt{describe} command.

<<dd_ignore>>
<<dd_do>>
sysuse auto, clear
describe
<</dd_do>>
<</dd_ignore>>

This produces the following Stata results:

<<dd_do>>
sysuse auto, clear
describe
<</dd_do>>

Now, we want to check if \texttt{mpg} is always greater than 0 and less than 100.
We use the \texttt{assert} command to perform the check.  In this case, we do not
want to include any output in the output text file, so we use the \texttt{quietly}
attribute to modify the behavior of the \texttt{dd_do} Stata dynamic tag.

<<dd_ignore>>
<<dd_do:quietly>>
assert mpg > 0 & mpg < 100
<</dd_do>>
<</dd_ignore>>

<<dd_do:quietly>>
assert mpg > 0 & mpg < 100
<</dd_do>>

If the data do not satisfy the conditions, \texttt{dyntext} will fail with an error
message, which will occur if we run the same \texttt{assert} command in a do-file.

Next, we want to summarize the \texttt{weight} variable:

<<dd_ignore>>
<<dd_do>>
summarize weight
<</dd_do>>
<</dd_ignore>>

This produces the following in the output text file:

<<dd_do>>
summarize weight
<</dd_do>>

We want to use the minimum and maximum values of \texttt{weight} in a sentence.
Instead of copying and pasting the numbers from the \texttt{summarize} output, we can
use the \texttt{dd_display} Stata dynamic tag with the \texttt{r(min)} and \texttt{r(max)}
stored results

<<dd_ignore>>
The variable weight has minimum value <<dd_display: %4.2f `r(min)'>> and
has maximum value <<dd_display: %4.2f `r(max)'>>.
<</dd_ignore>>

which produces the following in the output text file:

> The variable weight has minimum value <<dd_display: %4.2f `r(min)'>>
and has maximum value <<dd_display: %4.2f `r(max)'>>.

The \texttt{dd_display} dynamic tag uses Stata's \texttt{display} command to evaluate
expressions.  It can be used as a calculator. For example, if we want to
include the $range = max - min$ in a sentence, instead of calculating the
number and then copying and pasting it, we can use

<<dd_ignore>>
The variable weight has range <<dd_display: %4.2f `r(max)'-`r(min)'>>.
<</dd_ignore>>

which produces the following in the output text file:

> The variable weight has range <<dd_display: %4.2f `r(max)'-`r(min)'>>.

\end{document}