Re^3: Numeric as hash key returns undef...

It actually gets weirder than that -- the . (concatenation) operator has higher precedence than a hash's auto-stringification. This confused a somewhat baffling bug for a few hours recently...

use Data::Dumper;

$x{a}     = "bare a";
$x{"a.b"} = "quoted a.b";
$x{a.b}   = "unquoted a.b";
print Dumper(\%x);'

__DATA__
$VAR1 = {
          'ab' => 'unquoted a.b',
          'a.b' => 'quoted a.b',
          'a' => 'bare a'
        };
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Comment on Re^3: Numeric as hash key returns undef... Download Code

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Re^4: Numeric as hash key returns undef... by diotalevi (Canon) on Oct 24, 2006 at 21:46 UTC
a.b cannot be auto-stringified because it does not match the pattern `^\w+$`. What you're observing is the valid perl a.b becomng 'a'.'b' because strict allowed your bareword strings to be unquoted. At this point this has nothing to do with being a hash key. It's just that they're an expression. Enable strict to see what you were missing. ⠤⠤ ⠙⠊⠕⠞⠁⠇⠑⠧⠊	[reply] [d/l]