Re: size of an array ref

[swampyankee]

in reply to size of an array ref

A question I can still answer!

The size of a reference to an array is a scalar. If you're looking for the size of the array to which the references is pointing, you may try this:

print scalar(@{a});

The curly braces are the dereference operator. Now, if I misunderstood, and you want to know something like the total size of a array of references to arrays, my answer is likely useless.

[jethro]

Sorry to disappoint you but the curly braces do not dereference, @{a} is equivalent to @a. The curly braces only allow more complicated constructs with unambiguous precedence, for example ${$a[3]}[4] versus ${$a}[3][4]. If you want dereference, @{$a} or simply @$a is the right choice.

Update: Thanks to choroba and SuicideJunkie for spotting a $ where a @ should have been

[swampyankee]

Insert random cursing here. I should have kept my virtual mouth shut.

[Anonymous Monk]

:D Tutorials► Data Types and Variables► Data Type: Hash► references quick reference

[Marshall]

#!/usr/bin/perl -w
use strict;

my $aref = [5,6,7,8];
print @$aref,"\n";         #5678
print "@$aref","\n";       #5 6 7 8
print scalar @$aref,"\n";  #4
print ''.@$aref,"\n";      #4   

# using string concatenation in the last example
# puts @$aref in a scalar context

my $ref = [ [qw(a b c)], [qw(x y zzy)] ];
print ''.map{@$_}@$ref;   #6

# $ref is a ref to an array of references
# @$ref makes a list of those references
# the map expands out each array ref into all of its elements
# putting this into a scalar context reports the total number

print @{$ref->[1]},"\n";  #xyzzy

#basically, you need extra {} when a subscript is involved.