Re: The behavior of array and hash OPs

When you set/get a scalar from an array/hash, its value is copied:
Not always:


use strict;
use warnings;
use 5.010;

my @arr = (1, 2, 3);

for (@arr) {
  $_ *= 2;
}

print "@arr\n";

--output:--
2 4 6
[download]

Comment on Re: The behavior of array and hash OPs Download Code

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Re^2: The behavior of array and hash OPs by ikegami (Patriarch) on Jun 22, 2011 at 04:05 UTC
Yes, always. Unless you claim you can change the result of the multiplication after you assigned it, and that doing so changes the array.	[reply]
Re^2: The behavior of array and hash OPs by 7stud (Deacon) on Jun 22, 2011 at 06:01 UTC
How about if I claim that when perl gets the thing from the array, it is not a copy of the value because when I change it, the array changes?	[reply]
Re^3: The behavior of array and hash OPs by frieduck (Hermit) on Jun 22, 2011 at 16:05 UTC
How about you claim that "the foreach loop index variable is an implicit alias for each item in the list that you're looping over. " as mentioned in the perlsyn section on foreach?	[reply]
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Re^2: The behavior of array and hash OPs by llancet (Friar) on Jun 23, 2011 at 08:35 UTC
The array iterator is specially treated. If you use more 'common' way, it is copied by value: `$ perl -E 'my @array=qw/1 2 3/; my $first=$array[0]; $first=0; say "ar +ray: @array"; say "fetched changed: $first";' array: 1 2 3 fetched changed: 0` [download]	[reply] [d/l]