^hash_a.union[hash_b]
The method joins two hashes. It returns hash containing all keys from $hash_a and those keys from $hash_b, which are absent in $hash_a. The result has to be assigned to a new hash.
Example Code…
$man[
$.name[Jack]
$.age[22]
$.sex[m]
]
$woman[
$.name[Mary]
$.age[20]
$.weight[50]
]
$union_hash[^man.union[$woman]]
…will result in hash $union_hash: