how to uniqify a list of dict in python

Question

I have a list:

d = [{\'x\':1, \'y\':2}, {\'x\':3, \'y\':4}, {\'x\':1, \'y\':2}]

{\'x\':1, \'y\':2} comes more than once I want

Answer 1

Dicts aren't hashable, so you can't put them in a set. A relatively efficient approach would be turning the (key, value) pairs into a tuple and hashing those tuples (feel free to eliminate the intermediate variables):

tuples = tuple(set(d.iteritems()) for d in dicts)
unique = set(tuples)
return [dict(pairs) for pairs in unique]

If the values aren't always hashable, this is not possible at all using sets and you'll propably have to use the O(n^2) approach using an in check per element.