return an array of keys from hash when values match pattern

Question

I am trying to run through the following hash

my_family_pets_ages = {"Evi" => 6, "Hoobie" => 3, "George" => 12, "Bogart" => 4, "Poly" => 4, "Annabelle" => 0, "Ditto" => 3}

and return an array of the keys whose values match a specified integer for age. So, for example, if I wanted to find all of the pets that are 3 years old, it would return an array of just their names.

["Hoobie", "Ditto"]

I have the following method, but I can't seem to get the method to return an array of just the keys, but I keep just getting the key => value in an array like this:

["Hoobie"=>3, "Ditto"=>3]

Here is the method I have so far

def my_hash_finding_method(source, thing_to_find)
  source.select {|name, age| name if age == thing_to_find}
end

Any pointers? I'm stuck on how to return only the keys

Iuri G. · Accepted Answer · 2015-03-17 20:38:20Z

3

Just use #select, then #keys to get an array of the matching keys:

def my_hash_finding_method(source, thing_to_find)
  source.select { |name, age| age == thing_to_find }.keys
end

See Hash#keys for more information.

edited Mar 17, 2015 at 20:38

Iuri G.

10.6k4 gold badges25 silver badges39 bronze badges

answered Mar 17, 2015 at 20:29

theunraveler

3,28423 silver badges20 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

engineersmnky Over a year ago

Please add an explanation of this . The OP is obviously new to ruby so an explanation will make your answer more useful to them as well as other users with the same question.

Dirtsquad Over a year ago

thanks so much! I didn't know you could call the keys method on that entire block. very helpful!

theunraveler Over a year ago

The block just returns a Hash, so you can call any Hash instance methods you'd like on it.

Collectives™ on Stack Overflow

return an array of keys from hash when values match pattern

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related