[Rio-pm] [Golf] Função drop Haskell

Blabos de Blebe blabos em gmail.com
Quarta Fevereiro 3 13:05:23 PST 2010


Quem disse?


2010/2/3 Fernando Oliveira <fernandocorrea em gmail.com>:
> Mas o array não vem como referencia?
>
> Just another Perl Hacker,
> Fernando (SmokeMachine)
> http://perl-e.org
> Sent from Rio De Janeiro, RJ, Brazil
>
>
> Em 3 de fevereiro de 2010 19:00, Blabos de Blebe <blabos em gmail.com>
> escreveu:
>>
>> Sacanagem...
>>
>> sub drop{($a, em b)=@_;$a=0if$a<0;@b>1?@b[$a..$#b]:substr$b[0],$a}
>>
>>
>>
>> 2010/2/3 Fernando Oliveira <fernandocorrea em gmail.com>:
>> > 64:
>> >
>> > sub drop{($a,$b)=@_;$a=0if$a<0;ref$b?@$b[$a..$#$b]:substr$b,$a}
>> >
>> > Just another Perl Hacker,
>> > Fernando (SmokeMachine)
>> > http://perl-e.org
>> > Sent from Rio De Janeiro, RJ, Brazil
>> >
>> >
>> > Em 3 de fevereiro de 2010 18:33, Nilson Santos Figueiredo Jr.
>> > <acid06 em gmail.com> escreveu:
>> >>
>> >> Eu tenho certeza que vai dar pra alguém melhorar, ainda tá grande.
>> >> Mas se eu ficar mais tempo aqui tentando... vou ter meus dias inteiros
>> >> pra ficar brincando de Golf ao invés de ter um trabalho. ;-)
>> >>
>> >> -Nilson
>> >>
>> >> 2010/2/3 breno <breno em rio.pm.org>:
>> >> > Nilson, o final deveria dizer "mas é igual à versão do Nilson". Como
>> >> > eu fiz um monte de edições e contagens, acabou q foi enviado sem e eu
>> >> > nao percebi. O crédito e a menor tacada ainda são seus :-)
>> >> >
>> >> > []s
>> >> >
>> >> > -b
>> >> >
>> >> > 2010/2/3 Nilson Santos Figueiredo Jr. <acid06 em gmail.com>:
>> >> >> Breno,
>> >> >>
>> >> >> Essa que você mandou é exatamente igual a minha anterior, mas ao
>> >> >> invés
>> >> >> de $a,$b eu uso $n,$w.
>> >> >> Tem 65 chars fora e 55 dentro. Eu estava contando tudo.
>> >> >>
>> >> >> Mas essa tem um problema que retorna undef em alguns casos. Aí o
>> >> >> Mantovani que tem que falar se é certo ou não.
>> >> >>
>> >> >> -Nilson
>> >> >>
>> >> >> 2010/2/3 breno <breno em rio.pm.org>:
>> >> >>> 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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>> >> >>>>
>> >> >>>>
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