Re: Using 'keys' on a list

>Also, is there a way of creating a hash for consumption by 'keys' in the above situation which doesn't involve creating a hash reference from a list and then immediately dereferencing?

this is because hash hope first argument is a hash or array, so if offer a list the first argument is first element of list.
so keys just can't work on 'a' (in your example)...
if want keys work on return values of f(), the list still need stored into hash or array.

my %hash = f();
my @keys = keys %hash;
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but you hope finish in one line but don't want %{{}}
I can't offer any to avoid hash reference, but if the pupose just look tidy
maybe let subroutine f() return reference?
so we can use:

my @keys = keys %{f()};

#or in postfix dereferencing
my @keys = keys f()->%*;
[download]

hope this can help.

edit:I see you say you don't want :(

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Re^2: Using 'keys' on a list by Anonymous Monk on Jun 30, 2021 at 12:02 UTC
so keys just can't work on 'a' (in your example)... no, list in scalar context returns the last value	[reply]
Re^3: Using 'keys' on a list (update x2) by LanX (Saint) on Jun 30, 2021 at 12:32 UTC
> no, list in scalar context returns the last value That's wrong. A comma separated list returns the last value in scalar context, otherwise it always depends on the operator. update surrounding a LIST with `(...)[-1]` is a reliable way to get the last element `DB<7> x (1..5)[-1] 0 5 DB<8>` [download] update see also List's terminology and Parentheses in Perl Examples for "LIST", "list context", "list value", "list assigment", "list operator" Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply] [d/l] [select]
Re^4: Using 'keys' on a list (update x2) by Anonymous Monk on Jun 30, 2021 at 14:38 UTC
That's wrong. got an example of a "list in scalar context" or "comma operator in scalar context" or whatever that returns something other than the last value? `wantarray` is cheating	[reply] [d/l]
Re^5: Using 'keys' on a list (update x2) by The Perlman (Scribe) on Jun 30, 2021 at 15:29 UTC
Re^6: Using 'keys' on a list (update x2) by Anonymous Monk on Jun 30, 2021 at 15:35 UTC
Some notes below your chosen depth have not been shown here
Re^3: Using 'keys' on a list by The Perlman (Scribe) on Jun 30, 2021 at 13:21 UTC
A "list in scalar context" doesn't exist. - Ron	[reply]
Re^4: Using 'keys' on a list by Anonymous Monk on Jun 30, 2021 at 14:36 UTC
that doesn't make what glycine wrote any less wrong	[reply]
Re^5: Using 'keys' on a list by The Perlman (Scribe) on Jul 01, 2021 at 10:17 UTC

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