This for loop is unwilling to pass, no method error - ruby

Question

If I have:
#pet_shop = {
pets: [
{
name: "Sir Percy",
pet_type: :cat,
breed: "British Shorthair",
price: 500
},
{
name: "King Bagdemagus",
pet_type: :cat,
breed: "British Shorthair",
price: 500
}
]
}
I need a function that returns the pet if I give it the "name", so I have:
def find_pet_by_name(pet_shop, name)
for pet in pet_shop[:pets]
if pet[:name] == name
return pet
else return nil
end
end
end
But this is not passing the test. I get:
NoMethodError: undefined method `[]' for nil:NilClass
This is such a simple function, I do not know why it doesn't pass.

Answer 1

The problem with your code is that you do not complete the loop. You return either pet or nil for the first value of pet, namely, the "Sir Percy" hash. Your code should be as follows.
def find_pet_by_name(pet_shop, name)
for pet in pet_shop[:pets]
return pet if pet[:name] == name
end
nil
end
find_pet_by_name #pet_shop, "King Bagdemagus"
#=> {:name=>"King Bagdemagus", :pet_type=>:cat, :breed=>"British Shorthair",
# :price=>500}
I would suggest you instead use the method Enumerable#find.
name = "King Bagdemagus"
#pet_shop[:pets].find { |h| h[:name] == name }
#=> {:name=>"King Bagdemagus", :pet_type=>:cat, :breed=>"British Shorthair",
# :price=>500}
name = "Queen Bagdemagus"
#pet_shop[:pets].find { |h| h[:name] == name }
#=> nil
Incidentally, Rubiests rarely use for loops. (I've never used one). It's better to use an enumerator, such as each, find, select, reduce, in part because the value of the iteration variable (here pet) is not visible outside an enumerator's block.