Beefy Boxes and Bandwidth Generously Provided by pair Networks
Pathologically Eclectic Rubbish Lister

Re: Re: Re: Re: Non-destructive array processing

by Ovid (Cardinal)
on Jan 20, 2003 at 22:54 UTC ( #228516=note: print w/replies, xml ) Need Help??

in reply to Re: Re: Re: Non-destructive array processing
in thread Non-destructive array processing

Whoa! You're right. That doesn't seem to be very DWIM. The following snippet does not alter the elements of @array.

my @array = 1..10; my $r1 = sub { \@_ }->(@array); while (my @chunk = splice @$r1, 0, 2) { print "Chunk: @chunk\n"; } $_++ foreach @$r1; print "Original array is still intact! (@array)\n";

However, by moving the auto-increment line above the while loop:

my @array = 1..10; my $r1 = sub { \@_ }->(@array); $_++ foreach @$r1; while (my @chunk = splice @$r1, 0, 2) { print "Chunk: @chunk\n"; } print "Original array is not intact! (@array)\n";

This looks like some weird "copy on write" behavior that I was not aware of. Is this new, or is it Yet Another Feature that I didn't know about? :)

Update: Okay, I see that adrianh answered the question.


New address of my CGI Course.
Silence is Evil (feel free to copy and distribute widely - note copyright text)

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://228516]
and all is quiet...

How do I use this? | Other CB clients
Other Users?
Others lurking in the Monastery: (3)
As of 2018-02-24 18:40 GMT
Find Nodes?
    Voting Booth?
    When it is dark outside I am happiest to see ...

    Results (310 votes). Check out past polls.