It sounds like you're very new to the concept of programming as well.

The sprintf() function doesn't store anything. It takes in a set of input parameters and returns an output. It's a transformer, not a storehouse. You have to tell it where to store the result.

This means that you could do the following:

my @array_of_unformatted_numbers = (
    2, 5.3, 56.789,
);

my @array_of_formatted_numbers = map {
    sprintf( "%0.2d", $_ )
} @array_of_unformatted_numbers;

foreach my $formatted_number ( @array_of_formatted_numbers ) {
    print "The formatted number is $formatted_number.\n";
}
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