<font color="#82140F"><code>\.missingvalue.</code></font>';
(see <a href="Set.html#SetMissingValue">Set Missing Value</a>).
<p>
<li> `<font color="#82140F"><code>..num_col_data..</code></font>'
<!-- latex: \index{@code{..num_col_data..}, number column data} -->
Number of column data that exist.  You might want to use this after
`<font color="#82140F"><code>read columns</code></font>' to see if a data file actually had any data in it,
or use it in accessing individual elements of columns 
(see <a href="Rever