Beefy Boxes and Bandwidth Generously Provided by pair Networks
Problems? Is your data what you think it is?
 
PerlMonks  

Re: Re: Creating a copy of an array

by repson (Chaplain)
on Dec 19, 2000 at 06:37 UTC ( [id://47316]=note: print w/replies, xml ) Need Help??


in reply to Re: Creating a copy of an array
in thread Creating a copy of an array

How about: my @second = map { [ @$_ ] ] @first; That expands each element then creates a new array ref from it. Without the slowdown of a subroutine call like you used.

Still there are modules that can do this better.

Hell you could do this (not recommended, there are modules made for copying). 

use Data::Dumper qw/Dumper/;
my @first = ( ['1','2','3'],
             ['11','22','33'] );
my @second = @{ eval Dumper(\@first) };

[download]

Replies are listed 'Best First'.
Re: Re: Re: Creating a copy of an array
by ichimunki (Priest) on Dec 19, 2000 at 10:27 UTC
    Cool. I think using turning the sub into an expression is much better. So how does any module beat a one liner? :)
[reply]
      A one liner generally cannot take Everything into account. Since code may one day be reused in something else, something like my first snippet will work for the current problem but will be broken for others.

      My second snippet (with Data::Dumper) will work for most common problems of the copy type since it expands absolutely everything before recreating the structure. However using eval makes it likely to be slow, possibly insecure and less reliable.

      I suggest you have a good look at this article which provides a furthur in depth discussion of deep copying (which is what we are talking about here).

[reply]

In Section Seekers of Perl Wisdom

Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?

www.com | www.net | www.org
Node Status?
node history
Node Type: note [id://47316]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? • Last hour • Other CB clients
Other Users?
Others contemplating the Monastery: (4)
As of 2024-04-25 13:11 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found