This section describes the syntax which is used to extract elements that have been read into a variable from a database file. The syntax is an extension of the regular variable syntax used by the DI.

For a simple array read-in by the .DBARRAY command, you would use the syntax varname[row][column], where varname is the name of the variable defined by the .DBARRAY call, row is the number of the row you wish to access, and column is the column number. Row and column numbers start a 0. For instance, this would display the data in the second column of the first row of the file foo.txt:

<!--.dbarray myvar="foo.txt"-->
<!--.echo "The value is $myvar[0][1]"-->

If the row is omitted, then row 0 is assumed. So $myvar[0][5] and $myvar[5] are equivalent.

For an associative array read-in by the .DBHASH command, the syntax is varname[row]{keyname}, where varname is the name of the variable defined by the .DBHASH call, row is the number of the row you wish to access, and keyname is the name associated with the column. Keynames are not case-sensitive. For instance, this would display the data in the Comment column of the first row of the file foo.txt:

<!--.dbhash myvar="foo.txt"-->
<!--.echo "The value is $myvar[0]{comment}"-->

If the row is omitted, then row 0 is assumed. So $myvar[0]{comment} and $myvar{comment} are equivalent.

Examples:

These examples make use of the .DBDUMP command. Please refer to that section for more information.

Sample Data File:

# This is a comment line
path,description
/grafx/icons/bPrevious.gif,Previous Button
/grafx/icons/bIndex.gif,Index Button
/grafx/icons/bNext.gif,Next Button

Data read as an array:

<!--.dbarray array="dbtest.txt"-->
<table cellpadding=2>
  <tr> 
    <td></td>
    <td><font color=green>0</font></td>
    <td><font color=green>1</font></td>
  </tr>
  <!--.dbdump dbvar="$array" fmt='<tr>
    <td><font color=green>$row</font></td>
    <td>$array[$row][0]</td>
    <td>$array[$row][1]</td></tr>'--> 
</table>
<P>The value of $array[1][0] is <!--.echo "$array[1][0]"-->

The value of $array[1][0] is /grafx/icons/bPrevious.gif

Data read as a hash:

<!--.dbhash hash="dbtest.txt"-->
<table cellpadding=2>
  <!--.dbdump dbvar="$hash" fmt='<tr>
    <td><font color=green>$row</font></td>
    <td>$hash[$row]{path}</td>
    <td>$hash[$row]{description}</td>
  </tr>'--> 
</table>
<P>The value of $hash[1]{description} is <!--.echo "$hash[1]{description}"-->

The value of $hash[1]{description} is Index Button

Hashed data displayed as images:

<!--.dbdump dbvar="$hash" fmt='
  <img src="$hash[$row]{path}" alt="$hash[$row]{description}">'-->

You can also create and modify hashes and arrays using the .SET command:

<!--.
set myarray[0]="zero";
set myarray[1]="one";
set myarray[3]="three";
echo "<P>$&join(' | ','$myarray')";

set myhash{1}="value1";
set myhash{2}="value2";
set myhash{3}="value3";
echo "<FORM>Here's a popup: $&selectlist(choice1,2,hash='$myhash') </FORM>";
-->

zero | one | | three

Here's a popup: value1 value2 value3

Notice how an empty slot was automatically created in the array at index [2] when index [3] was assigned.

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