in reply to Re^13: Is there any difference between prototype % and @ ?
in thread Is there any difference between prototype % and @ ?

> And so far; neither you nor I have come up with a use case.

trivial example 

%salary=(
     boss      => 1_000,
     secretary => 300,
     admin     => 600,
     janitor   => 150,
    );

print
  map {"$_ earns $salary{$_} \n" }
  sort { $salary{$a} <=> $salary{$b} }
  grep { $salary{$_} > 500 }
  keys %salary;

[download]

translating it to hmap, hsort and hgrep is left as an excercise.

Cheers Rolf

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Re^15: Is there any difference between prototype % and @ ?
by BrowserUk (Patriarch) on Feb 24, 2013 at 08:37 UTC 

    sub hpairs (\%) {
    my $href = shift;
    map[ each %$href ], 1 .. keys %$href;
}

my %salary = (
    boss      => 1_000,
    secretary => 300,
    admin     => 600,
    janitor   => 150,
);

print for map { 
    "$_->[0] earns $_->[1]" 
} sort { 
    $a->[1] <=> $b->[1] 
} grep { 
    $_->[1] > 500 
} hpairs %salary;

__END__
admin earns 600
boss earns 1000

    [download]

    Or prettier:

    sub hpairs (\%) {
    use enum 'KEY', 'VAL';
    my $href = shift;
    map[ each %$href ], 1 .. keys %$href;
}

my %salary = (
    boss      => 1_000,
    secretary => 300,
    admin     => 600,
    janitor   => 150,
);

print for map {
    "$_->[KEY] earns $_->[VAL]"
} sort {
    $a->[VAL] <=> $b->[VAL]
} grep {
    $_->[VAL] > 500
} hpairs %salary;

    [download]
    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
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      nice, but

      1. doesn't even try to use the hmap or hgrep you defended for so long
      2. you needed to introduce a completely new function hpairs
      3. still needs a unhpairs to flatten LoA before assigning after chain to a new hash
      4. my hmap could already be used instead of your hpairs (and unhpairs) in this approach ...

      Let's count, you're going to introduce 5 new functions where I only need 3 to cover all discussed cases...

      You really hate symmetry, don't you?

      Cheers Rolf

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[select]

        1. doesn't even try to use the hmap or hgrep you defended so long

          I made no attempt to "defend". There is nothing to "defend".

          I offered an alternative, With reasoning. (I'm not forcing anyone to agree; nor use my ideas.)

        2. you needed to introduce completely new hpairs

          I use (or construct) the right tool for the job.

        3. still needs a unhpairs to flatten LoA before assigning to a new hash after chain

          Nothing new required, map serves the purpose perfectly.

        4. I could already use my hmap in your solution, so no need to create hpairs

          Look as hard as I might; I can't find your definition of hmap?

        5. you really hate symmetry, don't you?

          Nope! I "hate" very little. (And is that less "personal" that my recognising your ability?)

          But I do not seek to artificially impose symmetry where it does not naturally belong.

        With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]

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