square brackets? 1

[rotis23]

Hi All,

What's the difference between declaring an array using square or normal brackets?

Does it create a reference if they're square?

Thanks, rotis23

 

[Coderifous]

Can you provide an example of what you are talking about?

--jim

 

[rharsh]

rotis23,

I think you've got it right.

my @array = [] is an annoymous array and my @array = () is an empty list.

my @array = [];
print "With []: \|@array\|\n";

my @array1 = ();
print "With (): \|@array1\|\n";

produces output similar to:

With []: |ARRAY(0x1abf0b4)|
With (): ||

 

[mikevh]

my @array = [] is an annoymous array

To quibble, that's not quite true. @array is an array (not anonymous, it has a name) whose 1 element is a reference to an anonymous array. E.g.

#!perl
use strict;
use warnings;

my @array = [];
print "With []: \|@array\|\n";
[b]print scalar(@array), "\n";[/b]
print "\n";
my @array1 = ();
print "With (): \|@array1\|\n";
[b]print scalar(@array1), "\n";[/b]
print "\n";
[b]my $aref = [];
print "With (): \|$aref\|\n";
print scalar(@$aref), "\n";[/b]

Output:

With []: |ARRAY(0x225084)|
1

With (): ||
0

With (): |ARRAY(0x225138)|
0

Note the difference between @array and $aref.
@array is an array whose one element is a reference to an anonymous array. $aref is a reference to an empty anonymous array.

 

[rotis23]

Thought as much - cheers!

 

[mikevh]

my @array = []; is the equivalent of
my @array = ( [ ] );
Because you're assigning to an array, the parens are implied.

In my $aref = [];, assignment to a scalar, no parens implied.