Question

Complete programming beginner just trying to clarify something, I was creating keys for a hash and decided I wanted to delete one. Here were my guesses:

hash["key"].­delete
hash.dele­te["key"]

I eventually looked it up and I’m suppose to use ( ):

hash.dele­te("key")

Since I used a [ ] to create the hash, why wouldn’t I use it to delete a key? Also, and why wouldn’t hash("key").delete work?

Answer 1

[] is actually a method of Hash, and is treated specially in the language so the parameter goes between the []. It’s equivalent to store, which uses standard method syntax.

Likewise, delete is also a method, which takes one argument. Doing hash.delete['foo'] is trying to call delete (with no arguments), and then call [] on whatever it returns. Doing hash['foo'].delete is calling delete on whatever is stored in hash['foo'].