how to remove Duplicate values in list of list?

Question

I have a list like this:

 list_values=[("10",1),("10",2),("16",2),("16",1),("15",1)]

I want the result as :

 Result=[("10",1),("16",2),("15",1)]

can anyone help me?

Answer 1

Looks very much like How do you remove duplicates from a list whilst preserving order?, but just "carrying" the second element, not including it in the hash/comparison/whatever.

Two ways of doing this:

Either use a marker set to note down the occurrences of the first values:

list_values=[("10",1),("10",2),("16",2),("16",1),("15",1)]

seen = set()

seen_add = seen.add

result = []
for k,v in list_values:
    if k not in seen:
        seen_add(k)
        result.append([k,v])

print(result)

yields (preserves order):

[['10', 1], ['16', 2], ['15', 1]]

or use a dictionary on reversed items to keep the first value only:

result = list(dict(reversed(list_values)).items())

print(result)

yields (won't preserve order):

[('15', 1), ('10', 1), ('16', 2)]

Using collections.OrderedDict and reversing twice allows to preserve order too

import collections

result = list(reversed(list(collections.OrderedDict(reversed(list_values)).items())))

results in:

[('10', 1), ('16', 2), ('15', 1)]

That, unless Python 3.6+ is used, where dictionaries retain insertion order. From python 3.5 you can remove some forced list conversions so that will work:

list(reversed(collections.OrderedDict(reversed(list_values)).items()))

Answer 2

very bad that the OP not try or not show us some solution, but here the simple one:

list_values = [("10",1),("10",2),("16",2),("16",1),("15",1)]
Result = list(dict(reversed(list_values)).items())
print(Result)

will give you:

[('15', 1), ('16', 2), ('10', 1)]