one-liner to merge arrays (Re: A C-like brain in a Perl-like world)

my @merged = values %{{ map {$_ => $_ } @array1,@array2 }} ;
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The double-curlies are necessary - with single-curlies the interpreter whines and dies. If anyone can explain why, I'd be interested.

andy.

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(jeffa) Re: one-liner to merge arrays by jeffa (Bishop) on Sep 27, 2001 at 23:25 UTC
The reason why is because your map is evaluating into a hash reference, not a hash - values take a hash for it's argument, not a hash reference. Now, if you use a tempory hash reference instead, the reason for the double curlies becomes much more apparent: `my $hash = { map {$_ => $_ } @a,@b }; my @merged = values %{ $hash };` [download] Good question, by the way :) jeffa	[reply] [d/l]
Re: one-liner to merge arrays (Re: A C-like brain in a Perl-like world) by extremely (Priest) on Sep 27, 2001 at 23:42 UTC
Lets look at it blown out: `= values %{{ map {$_ => $_ } @a,@b }} ; = values # I want a hash and return a list %{ } # I turn a hashref into a hash { } # I turn a list into a hashref map { } @a,@b # I return a list from a list => , # We construct lists` [download] HTH... -- $you = new YOU; honk() if $you->love(perl)	[reply] [d/l]
Re: Re: one-liner to merge arrays (Re: A C-like brain in a Perl-like world) by andye (Curate) on Sep 28, 2001 at 15:09 UTC
Thanks extremely and jeffa, it's all clear now. I should have realised, since the array equivalent would be `@{[ ... ]}` , that the brackets were doing different things - but I'd managed to confuse myself. Cheers, Andy.	[reply] [d/l]