Re: Best way to copy an array?

assignments made to the copy don't affect the original, but the elements reference the same things initially.

Am I missing something? What exactly is wrong with @newlist = @{$self->{oldlist}};? What do you mean by "reference the same things initially?" Is this an array of references? Maybe you mean something like

@newlist = map { [ @$_ ] } @{ $self->{oldlist} };
@newlist = map { { %$_ } } @{ $self->{oldlist} };
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but it's hard to tell..

blokhead

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Re: Re: Best way to copy an array? by John M. Dlugosz (Monsignor) on Feb 23, 2004 at 04:37 UTC
Am I missing something? What exactly is wrong with `@newlist = @{$self->{oldlist}};`? I thought that doesn't copy anything, but aliases the array. You mean I'm copying a list every time I dereference it?! No, 'cause `push @{$self->{oldlist}}, $x` does indeed modify the thing being remembered by self. Ah, assigning to a @list naturally copies the elements and keeps the identity of the left-hand-side. That makes sence. Thanks, —John	[reply] [d/l] [select]

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Re: Re: Best way to copy an array?
by John M. Dlugosz (Monsignor) on Feb 23, 2004 at 04:37 UTC

Am I missing something? What exactly is wrong with @newlist = @{$self->{oldlist}};?

I thought that doesn't copy anything, but aliases the array. You mean I'm copying a list every time I dereference it?!

No, 'cause push @{$self->{oldlist}}, $x does indeed modify the thing being remembered by self.

Ah, assigning to a @list naturally copies the elements and keeps the identity of the left-hand-side. That makes sence.

Thanks,
—John

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