Question

我正在尝试使用哈希引用将信息传递给子例程。 Psuedo代码：

sub output_detail {
    Here I want to be able to access each record by the key name (ex. "first", "second", etc)
}

sub output_records {
    I want to use a foreach to pass each record has reference to another sub-routine
    that handles each record.

    foreach $key ( sort( keys %someting) ) {
        output_detail(something);
    }
}

%records = ();

while ($recnum, $first, $second, $third) = db_read($handle)) {
    my %rec = ("first"=>$first, "second"=>$second, "third=>$third);
    my $id = $recnum;
    $records{$id} = \%rec;
}

output_records(\%records);

我不确定在传递给子程序时如何取消引用哈希值。任何想法都会非常有用。

由于

Answer 1

使用->访问哈希引用的键。因此，您对output_records的参数将作为标量散列引用。

sub output_records {
    my $records = shift;
    my $first = $records->{"first"};
}

有关详细信息，请参阅perlreftut。

Answer 2

sub output_detail {
    my $hash = shift;
    my $value = $$hash{some_key};
}

sub output_records {
    my $hash = shift;

    foreach my $key (sort keys %$hash) {
        output_detail($hash, $key);  
        # or just pass `$$hash{$key}` if you only need the value
    }
}

如何访问已传递给子例程的哈希引用中的信息？

2 个答案: