Python List of Dictionaries[int : tuple] Sum [duplicate]

Question

I have a list of dictionaries. Each Dictionary has an integer key and tuple value. I would like to sum all the elements located at a certain position of the tuple.

Example:

myList = [{1000:("a",10)},{1001:("b",20)},{1003:("c",30)},{1000:("d",40)}]

I know i could do something like :

sum = 0
for i in myList:
    for i in myList:
        temp = i.keys()
        sum += i[temp[0]][1]
print sum

Is there a more pythonic way of doing this ? Thanks

Answer 1

Use a generator expression, looping over all the dictionaries then their values:

sum(v[1] for d in myList for v in d.itervalues())

For Python 3, substitute d.itervalues() with d.values().

Demo:

>>> sum(v[1] for d in myList for v in d.itervalues())
100