in reply to Re^7: Remove redundency from an array
in thread Remove redundency from an array

Oh, I see, sorry.

Actually, both jdporter and I got it wrong.
You don't modify $_ like jdporter thought.
You don't modify %_ like I thought.

Wow, that piece of code is so incredibly bad! You modify some random variable based on the current contents of $_. Whether it'll work or not is random. Most of the time, it won't. 

for (
   [qw(a a b c)],
   [qw(d e e f)],
) {
   print(uinq(@$_), "\n");    # Can't coerce array into hash
}

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for ('a a b c', 'd e e f') {
   print(uinq(split), "\n");  # Can't use string ("a a b c") as a HASH
+ ref while "strict refs" in use
}

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Adding local $_; causes the a specific variable to be used. That alieviates some of the problem, but that variable needs to be localized too. Why not just use %_?

As an expression: 

do { local %_; @_{@_}=(); keys %_ }

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As a sub: 

sub uinq { local %_; @_{@_}=(); keys %_ }

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Re^9: Remove redundency from an array
by mwah (Hermit) on Sep 24, 2007 at 20:39 UTC
    ikekami: Wow, that piece of code is so incredibly bad! ...

    Ok, ok, this is my first day on P.M. where I played around
    some time longer and tried to get used to the viewing habits of
    the holy men.

    So I learned I can't just give a simple
    example in order to state what's meant - no, one has to treat
    each code block by Test::Harness several times in each context
    available before posting - to avoid destructive criticism.

    So be it. Thanks for introducing me to P.M.


    Regards & good night (its past 22:00 in Europe ;-)

    mwa
[reply]
      I'll give the example, then 
      use Test::More tests => 2;

sub uinq {
   @_ = do { @$_{@_}=(); keys %$_ };
   @_
} 

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

%$_ = ( f=>'oo', b=>'ar' );
is keys(%$_), 2;
print "@{[ uinq @array ]}\n";
is keys(%$_), 2;

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[d/l]
        OK, this case *would* be solved by
        a local $_ before the do block (I confess ..)

        use strict;
use warnings;
use Test::More tests => 2;

sub uinq { local $_; @_ = do { @$_{@_}=(); keys %$_ } } 

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

%$_ = ( f=>'oo', b=>'ar' );
is keys(%$_), 2;
print "@{[ uinq @array ]}\n";
is keys(%$_), 2;

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        That correction seems to be all what's needed here.
        Thanks for clearing this up
        But now it's late ...

        Regards
        mwa
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