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in reply to Difference in Hash Declaration

Parenthesis () creates LIST:
( 1 => 'j', 2 => 'b' )
To create a hash, we substitute the LIST for %h:
my %h = ( 1 => 'j', 2 => 'b' );
Incidentally, LIST is different from ARRAY. To create an array, we substitute LIST for @a:
my @a = ( 1 => 'j', 2 => 'b' );