Identifying duplicate items in a list

Question

I want to figure out how to identify any case of identical items in a list.

Currently, there is a list of people and I want to first identify their surnames and put their surnames in a separate list called list_surnames.

Then I want to loop through that list and figure out whether there are instances of people having the same surname and if so I would add that to the amount value.

this code currently does not identify cases of duplication in that list.

Should be said I am brand new to learning programming, I apologize if code is horrible

group = ["Jonas Hansen", "Bo Klaus Nilsen", "Ida Kari Lund Toftegaard", "Ole Hansen"]
amount = 0

list_surnames = []
for names in group:
    new_list = names.split(" ")
    extract_surname = new_list[-1:]
    for i in extract_surname:
        list_surnames.append(i)
        for x in list_surnames:
            if x == list_surnames:
                amount += 1

print(list_surnames)
print(amount)

you should split up your problem. Make a list of surnames first. When that works, advance. — peer
– peer, Commented Sep 20, 2019 at 23:14
Possible duplicate of How do I find the duplicates in a list and create another list with them? — wjandrea
– wjandrea, Commented Sep 20, 2019 at 23:20
Stack Overflow is not a free code writing service. You are expected to try to write the code yourself. After doing more research if you have a problem you can post what you've tried with a clear explanation of what isn't working and providing a minimal reproducible example. I suggest reading How to Ask a good question. Also, be sure to take the tour — bfris
– bfris, Commented Sep 20, 2019 at 23:21

wjandrea · Accepted Answer · 2019-09-20 23:16:20Z

1

You can use the Counter to count

from collections import Counter
l = ["Jonas Hansen", "Bo Klaus Nilsen", "Ida Kari Lund Toftegaard", "Ole Hansen"]
last = [names.split()[-1] for names in l]
print(last)
c = Counter(last)
print(c)

edited Sep 20, 2019 at 23:16

wjandrea

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answered Sep 20, 2019 at 23:13

graham chow

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