When would it be useful?

Consider items from @list to be counted, with one "given" set and a "rest". A pre-initialized hash %h1 holds the "given" set and an empty hash %h2 counts the rest. Then we could: 

${\($h1{$_} // ($h2{$_} //= 0))}++ for @list;

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Greetings,
🐻

$gryYup$d0ylprbpriprrYpkJl2xyl~rzg??P~5lp2hyl0p$

In reply to Re^2: Logical/defined or as lvalue by jo37
in thread Logical/defined or as lvalue by jo37

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