How to dereference a reference to a hash or to an array in Perl
Moo with hash reference as attributes - with or without default values
ref - What kind of reference is this variable?
How to sort a hash in Perl?
How to sort a hash of hashes by value?
Reading CSV file as many hash-es
Can't use string (...) as an HASH ref while "strict refs" in use at ...
Useless use of hash element in void context
A hash and its uses - video
Creating a hash - video
Creating a hash from an array - video
Dumping a hash - video
Fetching data from a hash - video
exists, delete in hash - video
hash in SCALAR context - video
each - iterate over Perl hash elements pair-by-pair
Hashes in Perl
Fast lookup by name or by date - Array - Hash - Linked List
Search for hash in an array of hashes
The easiest way to find the highest hash value without looping through all of them (max)