How to get a slice of hash ref that a sub returns.

dmitri has asked for the wisdom of the Perl Monks concerning the following question:

I have a function that returns a hash reference. I want to get a slice of the returned hash reference without using a temporary variable. But it seems to be very tricky. This does not work:

sub x { return {qw(a b c d)}; }
print @{%{x()}}->{"a","b"};
[download]

While this does:

sub x { return {qw(a b c d)}; }
print %{x()}->{"a"};
[download]

How would I get a slice?

Comment on How to get a slice of hash ref that a sub returns. Select or Download Code

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Re: How to get a slice of hash ref that a sub returns. by TheHobbit (Pilgrim) on Apr 18, 2002 at 22:21 UTC
Hi, Simple, make it simple... `sub x {return {a => 1, b=> 2, c => 3}} print @{x()}{a,b}` [download] does the job. Cheers Leo TheHobbit GED/CS d? s-:++ a+ C++ UL+++ P+++>+++++ E+ W++ N+ o K? !w O? M V PS+++ PE-- Y+ PPG+ t++ 5? X-- R+ tv+ b+++ DI? D G++ e(++++) h r++ y+++()	[reply] [d/l]
Re: How to get a slice of hash ref that a sub returns. by dmitri (Priest) on Apr 18, 2002 at 21:48 UTC
OK, I got it (after I tried several million things): `sub x { return {qw(a b c d)}; } print @{%{x()}}{"a","c"};` [download] The trick was to kill the arrow (even though I am not yet sure why).	[reply] [d/l]
(tye)Re: How to get a slice of hash ref that a sub returns. by tye (Sage) on Apr 18, 2002 at 21:56 UTC
You can drop the %{}: `sub x { return {qw(a b c d)}; } print @{x()}{"a","c"};` [download] I find that references quick reference makes this stuff easy to remember. - tye (but my friends call me "Tye")	[reply] [d/l]