If you mean you currently format things with:

$result = "And the answer is $var1 (or $var2 percent)";
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and you want to pass in a format string, look at the 'sprintf' function instead. You can then do things like:

printit( "The answer is %s (or %d percent)" );

sub printit {
$format = shift @_;  # Passed in to function
...set variables...
$result = sprintf( $format, $var1, $var2 );
}
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