5 maximum values in a python dictionary
I have a dictionary like this:
A = {'a':10, 'b':843, 'c': 39,.....}
I want to get the 5 maximum values of this dict and store a new dict with this. To get the maximum value I did:
max(A.iteritems(), key=operator.itemgetter(1))[0:]
Perhaps it is an easy task, but I am stuck on it for a long time. Please help!!!
Answer
No need to use iteritems and itemgetter. The dict's own get method works fine.
max(A, key=A.get)
Similarly for sorting:
sorted(A, key=A.get, reverse=True)[:5]
Finally, if the dict size is unbounded, using a heap will eventually be faster than a full sort.
import heapq
heapq.nlargest(5, A, key=A.get)
For more information, have a look at the heapq documentation.