In Perl, how can I write the output of Dumper to a file?

Question

How can I make Data::Dumper write a dump into a file?

`Dumper()` simply outputs a string, use it like any other string going to a file (see below). — Jack M., Jul 14 '09 at 15:25
i have huge dump value , so i need to keep that into file and having look . — joe, Jul 14 '09 at 15:27

Sinan Ünür · Accepted Answer · 2009-07-14T16:45:31.080

26

Don't forget that you can specify the file handle to print to as in

print $LOG Dumper( \%some_complex_hash );

write_file 'mydump.log', Dumper( \%some_complex_hash );

Further thoughts: You might want to get into the habit of using:

warn Dumper( \%some_complex_hash );

and redirecting standard error to a file when you invoke your script (how you do this depends on the shell). For example:

 C:\Temp> sdf.pl 2>dump

edited Jul 14 '09 at 16:45

answered Jul 14 '09 at 15:18

Sinan Ünür

I'm curious: what advantage does File::Slurp offer here? – Telemachus Jul 14 '09 at 16:35
1

If all I want is to dump a complex data structure to a file for debugging purposes, it is more self contained than open / print / close: no filehandles or error messages to mess with. – Sinan Ünür Jul 14 '09 at 16:40
@SinanÜnür how is $LOG supposed to be used. should $LOG point to a file open ($LOG, '>', 'file.txt'); – patz Sep 02 '16 at 20:53
@patz `$LOG` is a file handle, as I clearly state up front. – Sinan Ünür Sep 02 '16 at 21:30

score 8 · Answer 2 · edited Jul 14 '09 at 15:28

8

The question is a bit unclear, but are you looking for something like this?

open my $FH, '>', 'outfile';
print $FH Dumper(\%data);
close $FH;

You can restore the data later by using eval.

edited Jul 14 '09 at 15:28

Sinan Ünür

answered Jul 14 '09 at 15:20

Michiel Buddingh

6

For storing and restoring later, Storable is a much better idea than Data::Dumper + eval: http://search.cpan.org/perldoc?Storable – Telemachus Jul 14 '09 at 16:37
1

Telemachus is correct. Storable, YAML, JSON, DBM::Deep or any of one million other serialization modules is a better choice than Data::Dumper + eval. – daotoad Jul 14 '09 at 17:01

score 8 · Answer 3 · answered Jul 14 '09 at 15:20

8

print FILE Data::Dumper->Dump($object);

answered Jul 14 '09 at 15:20

dsm

3 Answers3