(This is based on a friend's code, which was based on merlyn's code in a Web Techniques magazine article in January 1999.)

# In the configuration section...
my @Toggles = ('on', 'off');

# In some loop in the code...
$Toggles[$flip = !$flip]
[download]

I use this all the time, usually for background colors:

my @BGColors = ('#dddddd', '#ffffff');

for (1..10){ # As you loop through a database query result or somethin
+g
  print qq{
    <tr bgcolor="$BGColors[$flip = !$flip]">
      <td>$_</td>
    </tr>
  };
}
[download]

Voila!

An easily configured, pretty-to-behold alternating background color.

Notes:

• It's "just" a variable, so it interpolates well (a ternary operator or function call must happen outside quotes, or in @{[ ]} )
• You can "toggle between" more than 2 values like this:
  • initialize $flip to -1 somewhere before your loop
  • use preincrement and the modulus operator: (see below for full example)
    $Colors[$flip = ++$flip % 4];

# To cycle through any number of elements...
my @Cheers = ('hip', 'hip', 'hoo', 'ray');
my $flip = -1;
for (1..12){
  print "$Cheers[$flip = ++$flip % 4]\n";
}
[download]

Enjoy!

Russ

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