Question

In Perl, which of these is the “better” style?

$hash{"string"} or $hash{string}?

In any case, are they functionality identical?

Answer 1

From perldata perldoc:

In fact, an identifier within such curlies is forced to be a string, as is any simple identifier within a hash subscript. Neither need quoting. Our earlier example, $days{'Feb'} can be written as $days{Feb} and the quotes will be assumed automatically. But anything more complicated in the subscript will be interpreted as an expression. This means for example that $version{2.0}++ is equivalent to $version{2}++, not to $version{'2.0'}++

So yes fundamentally identical. However beware of gotchas:

sub is_sub { 'Yep!' }

my %hash;
$hash{ is_sub   } = 'Nope';
$hash{ is_sub() } = 'it is_sub!!';

say Dumper \%hash;

Will show:

$VAR1 = { 'is_sub' => 'Nope', 'Yep!' => 'it is_sub!!' };

My preference is for the bareword… but remember those () or a preceding + (see jrockway’s comment and answer) if you’re calling a sub 😉