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Python

Posted by Mona Jalal
Mona Jalal
4,302 Points

Why this always returns None besides the result?

''' We give you an Array of friend's list.

Write a method called greetingForAllFriends, with this signature:

greeting_for_all_friends(friends) This method takes an array of friends name and return a greeting messages Array.

Message sample: for the friend "Bilal" we get "Hello, Bilal!"

Rules:

If the argument is null, the method should return null/nil/None according to the given language (null for JS, None for Python and so on). If the argument is an empty array, the method should return null/nil/None, as stated above. If the argument is a valide array of strings, the method should return a hello message for every array entry

test.expect(greeting_for_all_friends(None) is None, "Must return None for None as input") test.expect(greeting_for_all_friends([]) is None, "Must return None for empty list as input") test.expect(greeting_for_all_friends(["Bilal"]) is not None, "Must not return None for an input") test.assert_equals(greeting_for_all_friends(["Bilal"]), ["Hello, Bilal!"])

'''

def greeting_for_all_friends(friends):
    if friends is None:
        return None
    else:
        for friend in friends:
            print("Hello, {}!".format(friend))

print(greeting_for_all_friends(['Tim']))

I get /Library/Frameworks/Python.framework/Versions/3.4/bin/python3.4 /Users/mona/PycharmProjects/PythonCodes/greeting_list.py Hello, Tim! None

1 Answer

Mona Jalal
Mona Jalal
4,302 Points

Solved:

def greeting_for_all_friends(friends):
    greeting_list = []
    if len(friends) == 0:
        return None
    if friends is None:
        return None
    else:
        for friend in friends:
            greeting_list.append("Hello, {}!".format(friend))
    return greeting_list
print(greeting_for_all_friends([]))