remove duplicate list elements

Question

I want to remove the duplicate elements in a list only when one element is repeated many times, like this:

li = ['Human','Human','Human'] => li = ['Human']

but not when there are two or more different elements:

li = ['Human','Monkey','Human', 'Human']

@S.Lott: I did that mistake too, but read the second line.. ^^ — poke, Sep 29 '10 at 22:20
@S. Lott. because he only wants duplicates removed if there is only one distinct value in the list. ordering might also be a concern. — aaronasterling, Sep 29 '10 at 22:20
This is homework. I saw it last semester. http://stackoverflow.com/questions/1549509/remove-duplicates-in-a-list-while-keeping-its-order-python, http://stackoverflow.com/questions/89178/in-python-what-is-the-fastest-algorithm-for-removing-duplicates-from-a-list-so-t, etc. — S.Lott, Sep 29 '10 at 22:23
Where did that answer disappear to? I thought that was correct? o.O — poke, Sep 29 '10 at 22:28
@poke I deleted it but I guess the damage was already done. I dropped out of high school so I guess I don't mind stealing OP's education if they're giving it away for free. It would be nice if that came with a piece of paper but oh well. — aaronasterling, Sep 29 '10 at 22:35

score 4 · Answer 1 · edited Jun 27 '11 at 09:35

4

You can do it easily with sets as below:

li = list(set(li))

edited Jun 27 '11 at 09:35

DarthJDG

answered Jun 27 '11 at 08:53

aaronasterling · Accepted Answer · 2010-09-29T22:16:50.063

3

def clean(lst):
    if lst.count(lst[0]) == len(lst):
        return [lst[0]]
    else:
        return lst

Does that do what you want?

if so, then you can do it in place as well

def clean_in_place(lst):
    if lst.count(lst[0]) == len(lst):
        lst[:] = [lst[0]]

edited Sep 29 '10 at 22:16

answered Sep 29 '10 at 22:05

aaronasterling

That works great! btw was how do you clean duplicates if the successive elements are same, like ['a','a','a','b','a','a'] to ['a','b','a'] – DGT Sep 29 '10 at 22:52

score 2 · Answer 3 · answered Apr 16 '12 at 06:06

2

lst = ['Human','Human','Human'] => lst = ['Human']
lst = ['Human','Monkey','Human', 'Human'] => lst = ['Human','Monkey','Human', 'Human']

it was do what you want?

if lst.count(lst[0])==len(lst):
   lst=list(set(lst))
   print lst 
else:
   print lst

answered Apr 16 '12 at 06:06

user1335578

3 Answers3