How to check if a specific key is present in a hash or not?

2018-06-21 16:59:16

I want to check whether the "user" key is present or not in the session hash. How can I do this?

Note that I don't want to check whether the key's value is nil or not. I just want to check whether the "user" key is present.

Hash 's key? method tells you whether a given key is present or not.

session.key?("user")

While Hash#has_key? gets the job done, as Matz notes here, it has been deprecated in favour of Hash#key? .

hash.key?(some_key)

In latest Ruby versions Hash instance has a key? method:

{a: 1}.key?(:a)
=> true

Be sure to use the symbol key or a string key depending on what you have in your hash:

{'a' => 2}.key?(:a)
=> false

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