如何使用 perl 遍历对象内的哈希数组

Question

我正在尝试遍历存储为 'Person' 对象的“_skills”属性的哈希数组，但遇到了问题。

test1.pl

my $person = new Person( "Hubert", "Blu",
    [
       {"name" => "Python", "Weight" => 80, "group","IT SKILLS", "id"=>0002},
       {"name" => "Magic", "Weight" => 100, "group", "MISC SKILLS", "id"=>0001},
       {"name" => "JavaScript","Weight" => 70, "group"=> "IT SKILLS", "id"=>0004},
       {"name" => "Mage","Weight" => 100, "group"=>"JOB TITLE", "id" =>0003},
       {"name" => "Assassin", "Weight" => 85, "group"=>"JOB TITLE"}
    ]
);

和Person.pl

sub new {
    my ($class,$first_name,$last_name,@skills) = @_ ;
    my $self = {};
    $self->{"_first_name"} = $first_name;
    $self->{"_last_name"} = $last_name;
    @{$self->{"_skills"}} = @skills;
    # Print all the values just for clarification.
    print "First Name is $self->{_first_name}\n";
    print "Last Name is $self->{_last_name}\n";
    print "Skills : " . Data::Dumper::Dumper($self->{_skills}) . "\n";


    print"---SKILLS---\n";
    my $i = 1;
    foreach my $skill_set (@{$self->{_skills}}) {
        print "skill ".$i .": \n";
        $i++;
        #print Data::Dumper::Dumper($skill_set) . "\n";
        print "$skill_set->{'_first_name'}";
    };
    bless $self, $class;
    return $self;
}

第一个转储显示数组，看起来不错。循环内的第二个转储再次显示整个数组，它只循环一次，然后出现以下错误

Not a HASH reference at /home/izoom/PerlTrainingGround/LeeR/lib/Person/Person.pm line 26.

被困了几个小时，一如既往地感谢您的帮助！

Answer 1

您将三个参数传递给 new 加上调用者。最后一个是对数组的引用。这意味着 @skills 以一个值为该引用的元素结束。

my $person = new Person( "Hubert", "Blu",
    [
       {"name" => "Python", "Weight" => 80, "group","IT SKILLS", "id"=>0002},
       {"name" => "Magic", "Weight" => 100, "group", "MISC SKILLS", "id"=>0001},
       {"name" => "JavaScript","Weight" => 70, "group"=> "IT SKILLS", "id"=>0004},
       {"name" => "Mage","Weight" => 100, "group"=>"JOB TITLE", "id" =>0003},
       {"name" => "Assassin", "Weight" => 85, "group"=>"JOB TITLE"}
    ]
);

应该是

my $person = new Person( "Hubert", "Blu",
   {"name" => "Python", "Weight" => 80, "group","IT SKILLS", "id"=>0002},
   {"name" => "Magic", "Weight" => 100, "group", "MISC SKILLS", "id"=>0001},
   {"name" => "JavaScript","Weight" => 70, "group"=> "IT SKILLS", "id"=>0004},
   {"name" => "Mage","Weight" => 100, "group"=>"JOB TITLE", "id" =>0003},
   {"name" => "Assassin", "Weight" => 85, "group"=>"JOB TITLE"}
);

或

    my ($class,$first_name,$last_name,@skills) = @_ ;

    @{$self->{"_skills"}} = @skills;     # Useless shallow array copy
       # -or-
    $self->{"_skills"} = [ @skills ];    # Same[1] but clearer
       # -or-
    $self->{"_skills"} = \@skills;       # No copy of elements

应该是

    my ($class,$first_name,$last_name,$skills) = @_ ;

    @{$self->{"_skills"}} = @$skills;    # Shallow array copy
       # -or-
    $self->{"_skills"} = [ @$skills ];   # Same[1] but clearer
       # -or-
    $self->{"_skills"} = $skills;        # No copy of elements

因为此时 $self->{"_skills"} 是 undef。

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