CODEWITHSUNDEEP
rubylanguage-design
Ajedi32
Ajedi32

Reputation: 48438

Why are Ruby hashes called hashes, and not maps, dicts, tables or associatve arrays?

In Ruby, there is a built-in class called Hash. According to the docs:

A Hash is a dictionary-like collection of unique keys and their values. Also called associative arrays, they are similar to Arrays, but where an Array uses integers as its index, a Hash allows you to use any object type.

...

A Hash can be easily created by using its implicit form:

grades = { "Jane Doe" => 10, "Jim Doe" => 6 }

So basically, they're associative arrays. If that's the case, then why are they called hashes? In Computer Science, isn't the term "hash" usually used to refer to a number or hexadecimal string of some kind generated by running some data through a hash function? In fact, Ruby objects even have a method called hash which "generates a Fixnum hash value for this object".

I'm aware that Hash in Ruby is implemented as a hash table, but given what I've said above that doesn't seem like enough justification for using the name Hash over something like Table or Map, especially given that Ruby doesn't seem to have any other built-in implementations of associative arrays. Why was this name chosen?

Upvotes: 8

Views: 862

Answers (1)

nobody
nobody

Reputation: 20184

Ruby takes a large amount of inspiration from Perl, and Perl calls this a hash.

UPDATE:

Confirmed by Yukihiro Matsumoto, creator of Ruby: https://twitter.com/yukihiro_matz/status/547516495249428480

Upvotes: 6

Related Questions