我有一个问题,我希望你能提供帮助吗?
这是我在理解哈希引用时需要帮助的最后一部分
代码:
my $content_lengths; # this is at the top
foreach my $url ( # ... more stuff
# compare
if ( $mech->response->header('Content-Length') != $content_length ) {
print "$child_url: different content length: $content_length vs "
. $mech->response->header('Content-Length') . "!\n";
# store the urls that are found to have different content
# lengths to the base url only if the same url has not already been stored
$content_lengths->{$url}->{'different'}->{$child_url} = $mech->response->header('Content-Length');
} elsif ( $mech->response->header('Content-Length') == $content_length ) {
print "Content lengths are the same\n";
# store the urls that are found to have the same content length as the base
# url only if the same url has not already been stored
$content_lengths->{$url}->{'equal'}->{$child_url} = $mech->response->header('Content-Length');
}
使用Data :: Dumper
的样子$VAR1 = {
'http://www.superuser.com/' => {
'difference' => {
'http://www.superuser.com/questions' => '10735',
'http://www.superuser.com/faq' => '13095'
},
'equal' => {
'http://www.superuser.com/ ' => '20892'
}
},
'http://www.stackoverflow.com/' => {
'difference' => {
'http://www.stackoverflow.com/faq' => '13015',
'http://www.stackoverflow.com/questions' => '10506'
},
'equal' => {
'http://www.stackoverflow.com/ ' => '33362'
}
}
};
我需要帮助:
我需要帮助了解访问哈希引用中不同部分的各种方法,并使用它们来执行操作,例如打印它们。
例如,我如何打印哈希引用中的所有$url
(即来自Data {Dumper的http://www.superuser.com/和http://www.stackoverflow.com/)
如何从$child_url
打印所有 $child_url
或特定的一个/子集等等?
非常感谢您对此的帮助,
非常感谢
答案 0 :(得分:1)
你可以这样导航你的hashref:
$hashref->{key1}{key2}{keyN};
例如,如果您想要超级用户等分支:
my $urlArrayref = $hashref->{'http://www.superuser.com/'}{'equal'};
更重要的是,要打印hashref的url(第一级键),你会这样做:
foreach my $key ( keys( %{$hashref} ) ) {
print( "key is '$key'\n" );
}
然后,如果你想要第二级密钥:
foreach my $firstLevelKey ( keys( %{$hashref} ) ) {
print( "first level key is '$firstLevelKey'\n" );
foreach my $secondLevelKey ( keys( %{$hashref->{$firstLevelKey}} ) ) {
print( "\tfirst level key is '$secondLevelKey'\n" );
}
}
等等......
-----编辑-----
这是上例中的示例代码:
#!/usr/bin/perl
use strict;
use warnings;
my $content_lengths = {
'http://www.superuser.com/' => {
'difference' => {
'http://www.superuser.com/questions' => '10735',
'http://www.superuser.com/faq' => '13095'
},
'equal' => {
'http://www.superuser.com/ ' => '20892'
}
},
'http://www.stackoverflow.com/' => {
'difference' => {
'http://www.stackoverflow.com/faq' => '13015',
'http://www.stackoverflow.com/questions' => '10506'
},
'equal' => {
'http://www.stackoverflow.com/ ' => '33362'
}
}
};
foreach my $key1 ( keys( %{$content_lengths} ) ) {
print( "$key1\n" );
foreach my $key2 ( keys( %{$content_lengths->{$key1}} ) ) {
print( "\t$key2\n" );
foreach my $key3 ( keys( %{$content_lengths->{$key1}{$key2}} ) ) {
print( "\t\t$key3\n" );
}
}
}
这导致此输出:
http://www.superuser.com/
difference
http://www.superuser.com/questions
http://www.superuser.com/faq
equal
http://www.superuser.com/
http://www.stackoverflow.com/
difference
http://www.stackoverflow.com/faq
http://www.stackoverflow.com/questions
equal
http://www.stackoverflow.com/