[Rio-pm] [Golf] Função drop Haskell

[breno]

fernando, nao pode funcionar pra valores negativos, vai entender :-)

acredito que assim funcione:

sub drop{($a,$b)=@_;$a=0if$a<0;ref$b?@$b[$a..$#{$b}]:substr$b,$a}

55 chars (dentro da sub).



2010/2/3 Fernando Oliveira <fernandocorrea em gmail.com>:
> 54:
>
> sub drop{($a,$b)=@_;ref$b?@$b[$a..$#{$b}]:substr$b,$a}
>
> Just another Perl Hacker,
> Fernando (SmokeMachine)
> http://perl-e.org
>
>
>
> Em 3 de fevereiro de 2010 17:54, Nilson Santos Figueiredo Jr.
> <acid06 em gmail.com> escreveu:
>>
>> Pronto, 80 caracteres (sem strict).
>> Estou satisfeito, agora é com vocês:
>>
>> sub
>> drop{($n,$w)=@_;$n=0if$n<0;ref$w?@$w[$n..$#{$w}]:$n>length$w?'':substr$w,$n}
>>
>> -Nilson
>>
>> 2010/2/3 Nilson Santos Figueiredo Jr. <acid06 em gmail.com>:
>> > Melhorando a minha solução anterior, 85 caracteres (83 tirando o my):
>> >
>> > sub drop{my($n,$w)=@_;$n=0
>> > if$n<0;ref$w?@$w[$n..$#{$w}]:$n>length$w?'':substr($w,$n)}
>> >
>> > -Nilson
>> >
>> > 2010/2/3 Nilson Santos Figueiredo Jr. <acid06 em gmail.com>:
>> >> Uma solução, warnings and strict compliant:
>> >>
>> >> sub drop {
>> >>    my ($n, $w) = @_;
>> >>    $n = 0 if $n < 0;
>> >>    return ( $n > length $w ? '' : substr($w,$n) ) if !ref $w;
>> >>    @$w[$n..$#{$w}];
>> >> }
>> >>
>> >> Se colocar tudo em uma linha:
>> >>
>> >> sub drop{my($n,$w)=@_;$n=0
>> >> if$n<0;return($n>length$w?'':substr($w,$n))if!ref$w;@$w[$n..$#{$w}];}
>> >>
>> >> 96 caracteres. Deve dar pra melhorar bastante ainda. Se tirar o "my"
>> >> pra deixar de ser strict compliant, cai pra 94.
>> >>
>> >> -Nilson
>> >>
>> >> 2010/2/3 Daniel de Oliveira Mantovani
>> >> <daniel.oliveira.mantovani em gmail.com>:
>> >>> Olá pessoal, o desafio envolve a função drop do Haskell:
>> >>>
>> >>> <haskell>
>> >>> ghci> myDrop 2 "foobar"
>> >>> "obar"
>> >>> ghci> myDrop 4 "foobar"
>> >>> "ar"
>> >>> ghci> myDrop 4 [1,2]
>> >>> []
>> >>> ghci> myDrop 0 [1,2]
>> >>> [1,2]
>> >>> ghci> myDrop 7 []
>> >>> []
>> >>> ghci> myDrop (-2) "foo"
>> >>> "foo"
>> >>> </haskell>
>> >>>
>> >>> Eu fiz em Perl, para ficar claro:
>> >>>
>> >>> <perl>
>> >>> sub drop {
>> >>>    my ( $n, $xs ) = @_;
>> >>>    if ( ref $_[1] ne 'ARRAY' ) {
>> >>>        $n <= 0 ? return $_[1] : return substr( $_[1], $n );
>> >>>    }
>> >>>    if ( $n <= 0 || !@_ ) {
>> >>>        return @{$xs};
>> >>>    }
>> >>>    else {
>> >>>        shift @{$xs};
>> >>>        drop( ( $n - 1 ), $xs );
>> >>>    }
>> >>> }
>> >>> </perl>
>> >>>
>> >>> Exemplos:
>> >>> mantovani em mantovani-desktop:~/Perl/Funcional$ perl -MHaskell -E 'say
>> >>> $_ for drop(3,[1,2,3,4,5,6])'
>> >>> 4
>> >>> 5
>> >>> 6
>> >>>
>> >>> mantovani em mantovani-desktop:~/Perl/Funcional$ perl -MHaskell -E 'say
>> >>> $_ for drop(1,"ofernandoagoragolf")'
>> >>> fernandoagoragolf
>> >>>
>> >>> mantovani em mantovani-desktop:~/Perl/Funcional$ perl -MHaskell -E 'say
>> >>> $_ for drop(2,["mantovani","garu","fernando","blabos"])'
>> >>> fernando
>> >>> blabos
>> >>>
>> >>> mantovani em mantovani-desktop:~/Perl/Funcional$ perl -MHaskell -E 'say
>> >>> $_ for drop(-1,["mantovani","garu","fernando","blabos"])'
>> >>> mantovani
>> >>> garu
>> >>> fernando
>> >>> blabos
>> >>>
>> >>> mantovani em mantovani-desktop:~/Perl/Funcional$ perl -MHaskell -E 'say
>> >>> $_ for drop(-1,"mantovani")'
>> >>> mantovani
>> >>>
>> >>> mantovani em mantovani-desktop:~/Perl/Funcional$ perl -MHaskell -E 'say
>> >>> $_ for drop(10,"mantovani")'
>> >>>
>> >>> --
>> >>> "If you’ve never written anything thoughtful, then you’ve never had
>> >>> any difficult, important, or interesting thoughts. That’s the secret:
>> >>> people who don’t write, are people who don’t think."
>> >>> _______________________________________________
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>> >>>
>> >>
>> >
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