Are we talking empty string or undef here? They act differently, depending.

Normally they do, but we're talking about hash keys here. A hash key can only be a string, so any number, reference or undefined value is stringified. undef happens to stringify to the emtpy string, so $foo{+undef} and $foo{''} are the same thing. 

2;0 juerd@ouranos:~$ perl -le'$foo{+undef} = "Hello, world!"; print $f
+oo{""}'
Hello, world!

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In reply to Re: Re: null keys by Juerd
in thread null keys by hakkr

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