Data::Dumper

[geektron]

Item Description: takes a variable ( or reference to a variable) and 'unrolls' or dumps it out for inspection

Review Synopsis: invaluable for object design and debugging complicated data structure

Data::Dumper is in the standard Perl distribution. it's probably the easiest module to use, just issue a 'use Data::Dumper' call, and then either print to STDOUT ( with 'print Dumper \@foo ') or stick into some html used by an application ( i prefer to wrap it in <pre> tags, so the output isn't mangled.) Data::Dumper also works keenly with objects, and gives you the class into which your variable is blessed. (with makes debugging object relations really quick.)

[tilly]

Stupid Data::Dumper trick. Set $Data::Dumper::Indent to 1 and dump a reference to a data structure. What you get is readable to humans, and makes a very convenient format for a configuration file. Just do the file to read the configuration. No work definining a format. No worries about whether or not everything is escaped...

[Adam]

I'm always forgeting the way to get Data::Dumper to print a hash and put the name of the hash in-place of the "$VAR". So this is as good a place as any to stick it where I can find it quickly, and other people can see an example usage.

use strict;
use Data::Dumper;
my %hash = ( 'some' => 'stuff' );
print Data::Dumper->Dump([\%hash], ["hashname"]), $/;

[dkubb]

Here's an example of how I use Data::Dumper, on one line, during debugging. It produces a pretty clean output of the data structure:

print Data::Dumper->new([\%hash],[qw(hash)])->Indent(3)->Quotekeys(0)->Dump;

[Anonymous Monk]

Another Data::Dumper trick- For quick and dirty state persistence over multiple invocations of a program, use a single hash for all your state info. Dumper() a reference to it into a file when the program exits, and require() that file the next time the program starts up. booom. You're right back where you left off.

[lachoy]

Big 'me too' along with tilly for using Data::Dumper for configuration files.

In addition I must say that my debugging life would be much more painful in a world without Data::Dumper. Curious about what's in that hairy list of hashes of lists of hashes? Just Dump It!

All hail Data::Dumper!

[princepawn]

However, your curiosity for the contents of code refs will never be satisfied, nor will you serialize them to disk, or ever de-serialize them and resurrect them, for this is not possible in Perl5. And probably not Perl 6.

But it is a serious shortcoming that doesn't exist in many other scripting languages.

Prince "Why cant we preview replies?!" Pawn

[premchai21]

See Re: storable.pm+CODE refs.

[premchai21]

I prefer Data::Denter, myself.

[Anonymous Monk]

Look At Data::TreeDumper. Muchhh more readable.