in reply to Remove redundency from an array

This is, as has shown here, a fairly
often used and well documented task.

Sometimes I'd use snippet that reads like
  my @array = (1,1,3,3,2,3,5,7,5,2);

  # uniqify without modules 
  @array = do { @$_{@array} = (); keys %$_ };

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Regards

M.

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Re^2: Remove redundency from an array
by jdporter (Paladin) on Sep 24, 2007 at 18:56 UTC

    Of course, that clobbers $_. Perhaps you want to insert 

    local *_;

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    at the beginning of that do block.

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      jdporter: Of course, that clobbers $_. Perhaps you want to insert local *_; ...

      Would this (*_) be relevant here?

      $_ *might* be localized, but *_ imho not.

      consider: 
      sub uinq {
   # local *_;  # <== will fail, $_ will work
   @_ = do { @$_{@_}=(); keys %$_ }; @_
} 

my @array = (1,1,3,3,2,3,5,7,5,2);

print "@{[ uinq @array ]}\n";

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      Regards & thanks
      mwa
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        First, local *_ does work if you put it in the do block like jdporter said.

        Secondly, local $_ won't work. It'll compile, but that doesn't count for anything if it doesn't do what needs to be done. We want to protect the parent's %_.

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        Good point. It's up to you (the programmer) to protect/preserve the contents of @_ if necessary. It wasn't necessary in the code you gave.

        ikegami may be too modest to point out his previous discursion on the subject.

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Re^2: Remove redundency from an array
by Roy Johnson (Monsignor) on Sep 24, 2007 at 21:48 UTC
    Better to use either a lexical hash in the do-block, or an anonymous hash:
    @array = keys %{ {map {$_,undef} @array} };
    Caution: Contents may have been coded under pressure.
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