Find the repeated element in a list in Python-CodePudding

i have two lists here. What should i do to display the all common friends and not only one of them(With an explanation for it)? Thanks!

def common_friend(Name1, Name2):
   for i in Name1 and Name2:
    common_friend = i

   if common_friend in Name1 and Name2:
    
    print(f"The common friend is: {common_friend}")

Nico = ["Nicole", "Mo", "Jani", "Maik", "Lena"]

Younes = ["Johannas", "Sara", "Basem","Lena", "Philip", "Mo"]

common_friend(Nico, Younes)

CodePudding user response：

What you describe sounds like set intersection; I would turn the lists into sets and use the intersection operator:

>>> Nico = {"Nicole", "Mo", "Jani", "Maik", "Lena"}
>>> Younes = {"Johannas", "Sara", "Basem","Lena", "Philip", "Mo"}
>>> Nico & Younes
{'Mo', 'Lena'}

Mo and Lena are the common friends of Nico and Younes.

Sets are described in the tutorial as well as in the reference; both also show how you can convert existing lists (actually, any iterable) to sets.

CodePudding user response：

def common_friend(friend_1, friend_2):
    common_friends = []
    for name_1 in friend_1:
        if name_1 in friend_2:
            common_friends.append(name_1)

    return common_friends


Nico = ["Nicole", "Mo", "Jani", "Maik", "Lena"]

Younes = ["Johannas", "Sara", "Basem", "Lena", "Philip", "Mo"]

common_friends = common_friend(Nico, Younes)


print(common_friends)   # ['Mo', 'Lena']

CodePudding user response：

If you like or should stick with interating over the list of names, changing your code to the following should solve your question.

def common_friend(Name1, Name2):
    # iterate over all names in `Name1` e.g. friends of Nico
    # as the common friends needs to be in both lists,
    # we can just iterate over one of them to check for common friends
    for name in Name1:
        # check if the name is in the list of `Name2`, e.g. the friends of Younes
        # as we iterate over alle Names in `Name1` we do not need to check for `if name in Name1`
        if name in Name2:
            print(f"The common friend is: {name}")

Nico = ["Nicole", "Mo", "Jani", "Maik", "Lena"]
Younes = ["Johannas", "Sara", "Basem","Lena", "Philip", "Mo"]

common_friend(Nico, Younes)

CodePudding user response：

The simplest solution would be to iterate over both list and find duplicates:

for nicos_friend in Nico:
    for younes_friend in Younes:
        if nicos_friend == younes_friend:
            print(f'Same friend {nicos_friend}')

or simplier:

for nicos_friend in Nico:
    if nicos_friend in Younes:
        print(f'Same friend {nicos_friend}')

CodePudding user response：

You can use the intersection of sets for that:

Nico = ["Nicole", "Mo", "Jani", "Maik", "Lena"]
Younes = ["Johannas", "Sara", "Basem","Lena", "Philip", "Mo"]

list(set(Nico).intersection(set(Younes)))

Output:

['Lena', 'Mo']