foreach keys possible using a hash reference?

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

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Re: foreach keys possible using a hash reference? by Abigail-II (Bishop) on Jul 04, 2002 at 17:10 UTC
The rule on what the syntax is when dealing with references is very simple. Wherever you use something of the form `sigil` followed by the name of a variable (scalar, hash, array, subroutine), you may replace the name of the variable with a block whose result is a reference to the appropriate type. So, where you normally would write `keys %hash` [download] you now replace `hash` with a block returning a reference to a hash, and you get: `keys %{$hashref}` [download] The block has a very, very simple statement, the statement is just an expression consisting of a single variable. As an extra feature, in such a simple expression, you may omit the braces, so you will end up with: `keys %$hashref` [download] Abigail	[reply] [d/l] [select]
Re: foreach keys possible using a hash reference? by gav^ (Curate) on Jul 04, 2002 at 17:03 UTC
Something like this would do the trick: `foreach (keys %$args) { # do something }` [download] gav^	[reply] [d/l]
Re: foreach keys possible using a hash reference? by amphiplex (Monk) on Jul 04, 2002 at 17:04 UTC
this should do: `my %h = ( 'a' => 1, 'b' => 2, 'c' => 3, ); print_hash(\%h); sub print_hash { my $h = shift; for (keys %$h) { print "$_: $h->{$_}\n"; } }` [download] ---- kurt	[reply] [d/l]
Re: foreach keys possible using a hash reference? by impossiblerobot (Deacon) on Jul 04, 2002 at 21:53 UTC
I would also suggest perlreftut, which details five simple rules for creating and de-referencing references, and really simplifies things. Impossible Robot	[reply]
Re: foreach keys possible using a hash reference? by Juerd (Abbot) on Jul 04, 2002 at 19:48 UTC
Everything you need to know about references is in perlref. - Yes, I reinvent wheels. - Spam: Visit eurotraQ.	[reply]


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