Skip to Main Content
Perl in a Nutshell, 2nd Edition
book

Perl in a Nutshell, 2nd Edition

by Nathan Patwardhan, Ellen Siever, Stephen Spainhour
June 2002
Beginner content levelBeginner
759 pages
80h 42m
English
O'Reilly Media, Inc.
Content preview from Perl in a Nutshell, 2nd Edition

Creating References

You can create a reference to an existing variable or subroutine by prefixing it with a backslash:

$a = "fondue";
@alist = ("pitt", "hanks", "cage", "cruise");
%song = ("mother" => "crying", "brother" => "dying");
sub freaky_friday { s/mother/daughter/ }
# Create references
$ra = \$a;
$ralist = \@alist;
$rsong = \%song;
$rsub = \&freaky_friday; # '&' required for subroutine names

References to scalar constants are created similarly:

$pi = \3.14159;
$myname = \"Charlie";

Note that all references are prefixed by a $, even if they refer to an array or hash. All references are scalars; thus, you can copy a reference to another scalar or even reference another reference:

$aref = \@names;
$bref = $aref;            # Both refer to @names
$cref = \$aref;           # $cref is a reference to $aref

Because arrays and hashes are collections of scalars, you can create references to individual elements by prefixing their names with backslashes:

$star = \$alist[2];       # Refers to third element of @alist
$action = \$song{mother}; # Refers to the 'mother' value of %song
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Start your free trial

You might also like

Perl by Example, Fourth Edition

Perl by Example, Fourth Edition

Ellie Quigley
Perl Cookbook, 2nd Edition

Perl Cookbook, 2nd Edition

Tom Christiansen, Nathan Torkington
Perl in a Nutshell

Perl in a Nutshell

Nathan Patwardhan, Ellen Siever, Stephen Spainhour
Learning Perl, 7th Edition

Learning Perl, 7th Edition

Randal L. Schwartz, brian d foy, Tom Phoenix

Publisher Resources

ISBN: 0596002416Errata Page