My list is like this
list = [('N',''),('N',''),('K','asdf'),('K','asw'),('S','aqq'),('N',''),('N',''),('N','')]
I want change this list to
list_1 = [('N',''),('K','asdf'),('K','asdf'),('S','aqq'),('N','')]
only duplicated N should be removed..
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Arcanes
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possible duplicate of [Removing elements that have consecutive dupes](http://stackoverflow.com/questions/5738901/removing-elements-that-have-consecutive-dupes) – Bhargav Rao Jun 09 '15 at 12:02
2 Answers
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You can use itertools.groupby and grab the first item out of each group using next.
>>> import itertools
>>> l = [('N',''),('N',''),('K','asdf'),('K','asw'),('S','aqq'),('N',''),('N',''),('N','')]
>>> [next(group) for key, group in itertools.groupby(l)]
[('N', ''), ('K', 'asdf'), ('K', 'asw'), ('S', 'aqq'), ('N', '')]
Edit:
If you just want to remove the consecutive duplicates of the tuples starting with 'N' then you can use
>>> [key if key[0] == 'N' else list(itertools.chain.from_iterable(group)) for key, group in itertools.groupby(l)]
[('N', ''), ['K', 'asdf'], ['K', 'asw'], ['S', 'aqq'], ('N', '')]
Cory Kramer
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Oh, I just want to remove having 'N' tuple. If i use that code, when i change ('K','asw') to ('K','asdf) then 'K' tuple also removed – Arcanes Jun 09 '15 at 12:11
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simply you can use set to remove duplicates
>>> old_list
[('N', ''), ('N', ''), ('K', 'asdf'), ('K', 'asw'), ('S', 'aqq'), ('N', ''), ('N', ''), ('N', '')]
>>> list_1 = list((set(old_list)))
>>> list_1
[('K', 'asdf'), ('N', ''), ('K', 'asw'), ('S', 'aqq')]
Ravi Kumar
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The OP only wants to remove consecutive duplicates, not all duplicates – Cory Kramer Jun 09 '15 at 14:05
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@arcanes if you want order and to remove consecutive duplicates then my answer not work for you.. – Ravi Kumar Jun 09 '15 at 14:58