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电梯直达

1楼 [收藏(0)] [报告]

发表于 2008-01-23 09:54 |只看该作者 |倒序浏览

sub new {
  my ($class, $genes) = @_;

  my $self;
  if (ref $class) {
$self = bless {} => ref $class;
$self->{$_} = $class->{$_} for keys %$class;
$self->{GENES}  = $genes;
$self->{CALCED} = 0;

  } else {       # new mode. Genome is given
goto &newSpecific;
  }

  return $self;
}

还有一个
sub newRandom {
  my ($class, $length) = @_;

  my $self = bless {
      GENES => [],
      SCORE => 0,
      FITFUNC => sub {},
      CALCED  => 0,
   } => $class;

  push @{$self->{GENES}} => rand > 0.5 ? 1 : 0
for 1 .. $length;

  return $self;
}

$self = bless 中的=> 号不理解，
push @{$self->{GENES}} => rand > 0.5 ? 1 : 0 这里面的=> 也不理解，有没有高手解答一下了先谢谢了！

[ 本帖最后由 killer5757 于 2008-1-23 10:47 编辑 ]

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apile

富足长乐

论坛徽章:: 1

2楼 [报告]

发表于 2008-01-23 12:58 |只看该作者

=> equal to ,
please reference to
perldoc perl

   The "=>" operator is a synonym for the comma, but forces any word (con-
   sisting entirely of word characters) to its left to be interpreted as a
   string (as of 5.001).  This includes words that might otherwise be con-
   sidered a constant or function call.

         use constant FOO => "something";

         my %h = ( FOO => 23 );

   is equivalent to:

         my %h = ("FOO", 23);

   It is NOT:

         my %h = ("something", 23);

   If the argument on the left is not a word, it is first interpreted as
   an expression, and then the string value of that is used.

   The "=>" operator is helpful in documenting the correspondence between
   keys and values in hashes, and other paired elements in lists.

            %hash = ( $key => $value );
            login( $username => $password );

[ 本帖最后由 apile 于 2008-1-23 13:00 编辑 ]

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兰花仙子

版主

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3楼 [报告]

发表于 2008-01-23 19:49 |只看该作者

$self = bless 中的=> 号不理解，
push @{$self->{GENES}} => rand > 0.5 ? 1 : 0 这里面的=> 也不理解，有没有高手解答一下了先谢谢了！

1. =>在perl里就是逗号',', 第一句就等同于bless {},$class,返回一个bless的目标给$self. ref $class表示如果该类已实例化的话,那么就取其类自身.
2. rand是个内置函数吧,如果call该函数的结果大于0.5,就push 1到$self->{GENES}指向的数组里去.否则push 0到这个数组里去.
3. 这个代码写的有点晦涩.另外,现代好的programming style建议不用goto语句.

btw: 好久没用中文,','是句号还是逗号刚才想了半天,