Perl hash Data::Dumper

问题:

In Perl I need to analyze a huge hash, so I print it into a file using Data::Dumper module. Because it is a huge file, it is very hard to read. Is it possible somehow to print Dumper output nicely, so when I will find a string that I am looking for, I will be able to see immediately key structure where the string I am looking for is stored?

Currently I am using just a simple code:

            use Data::Dumper;
            ...
            print Dumper $var;

What is the best syntax or alternative to get nice output?

回答1:

I almost always set

$Data::Dumper::Indent = 1;
$Data::Dumper::Sortkeys = 1;

with Data::Dumper. The first statement makes the output more compact and much more readable when your data structure is several levels deep. The second statement makes it easier to scan the output and quickly find the keys you are most interested in.

If the data structure contains binary data or embedded tabs/newlines, also consider

$Data::Dumper::Useqq = 1;

which will output a suitable readable representation for that data.

Much more in the perldoc.

回答2:

One possible solution is to use Data::Dumper::Perltidy which runs the output of Data::Dump through Perltidy.

#!/usr/bin/perl -w

use strict;
use Data::Dumper::Perltidy;

my $data = [{ title => 'This is a test header' },{ data_range =>
           [ 0, 0, 3, 9] },{ format     => 'bold' }];

print Dumper $data;

__END__

Prints:

$VAR1 = [
    { 'title'      => 'This is a test header' },
    { 'data_range' => [ 0, 0, 3, 9 ] },
    { 'format'     => 'bold' }
];

Another way is to use Data::Dump.

回答3:

$Data::Dumper::Sortkeys = 1;

If you want to get a more reliable result then you have to follow the dumper next. Put in the suitable word to operate that function.

回答4:

This answers the question.

my $WWW_Scripter_Plugin_JavaScript_JE = ${ $VAR1->[1]{156192192} };
my $JE_Object_String = ${ $WWW_Scripter_Plugin_JavaScript_JE->{pf}{String} };
my $JE_Object_Function = ${ $JE_Object_String->{props}{search} };
my $REF = ${ $JE_Object_Function->{global} };
my $HTML_DOM_Element_Img = $REF->{classes}{'HTML::DOM::Element::Img'};

It also violates encapsulation. Perl lets you do it, but you should rather ask how to get at the data with the published WWW::Scripter API.