I'd like to replace part of a string with asterisks (obfuscating credit card numbers on a receipt.) Here's what I have already: 
my $string = '5424123412345678';
substr($string,0,-4,'*' x (length($string) - 4));
print $string;

[download]
Can you think of a "better" way to do it? Meaning faster, cleaner, and/or shorter.

Update: No hard-coded asterisk strings, because not all credit card numbers are the same length. Also, consider this slight change to my original code: 
my $string = '5424123412345678';
substr($string,4,-4,'*' x (length($string) - 8));
print $string;

[download]
That simple change will obfu all but the first four and last four digits. Play with that idea, if you'd like.

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It's all fine and dandy until someone has to look at the code.

In reply to Golf: Replacing part of a string with "*" by kwaping

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