condtional logic within variables

[Anon]

How can you do the following:

$first_name = 'John';
$last_name = 'Doe';

$message = "
Dear $first_name if (isset ($last_name)) {$last_name},
Thank you for your interest...
";

I realize the above code does not work but how would one put conditional logic within a variable.

I need to gather form data to put into the body of an email but some of the form data is not required.

[lxghak]

$first_name = 'John';
$last_name = 'Doe';

printf('Dear %s %s, thank you for your...', $first_name, isset($last_name)?$last_name:'');

There ya go.

[Anon]

But what I want to is use conditional logic for the declaration of a variable, not just to print it. I need to define $message (conditionally) to pass on to the mail() function.

[lxghak]

$first_name = 'John';
$last_name = 'Doe';

$message = sprintf('Dear %s %s, thank you for your...', $first_name, isset($last_name)?$last_name:'');

There ya go, again =P