I want to "scrub" a second string of all characters which are not in the first string. Thus:

scrub 'pure', 'p!u-r-*e'; # returns pure
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Here is the code I wrote. It works, but I was hoping there was a module or something which already did this.

sub string_clean {
  my ($pure, $dirty) = @_;

  my @pure  = (split //, $pure) ;
  my @dirty = (split //, $dirty) ;
  my %pure  = map { ($_ => 1) } @pure;

  my @cleaned = grep { $pure{$_} } @dirty;
  return join '', @cleaned;
}
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slickness

staring at the sample code, I'm thinking how slick it would look to call the function like this:

scrub 'impure' => 'pure' ; # yields 'pure'
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you know... use the arrow to show the transition from dirty to clean... real English-like.