How to iterate over two dictionaries at once and get a result using values and keys from both

Question

def GetSale():#calculates expected sale value and returns info on the stock with              highest expected sale value
      global Prices
      global Exposure
              


        

Answer 1

The question isn't well defined, and the answer accepted will fail for some dictionaries. It relies on key ordering, which isn't guaranteed. Adding additional keys to a dictionary, removing keys, or even the order they are added can affect the ordering.

A safer solution is to choose one dictionary, d in this case, to get the keys from, then use those to access the second dictionary:

d = {'a':5, 'b':6, 'c': 3}
d2 = {'a':6, 'b':7, 'c': 3}
[(k, d2[k], v) for k, v in d.items()]

Result:

[('b', 7, 6), ('a', 6, 5), ('c', 3, 3)]

This isn't more complex than the other answers, and is explicit about which keys are being accessed. If the dictionaries have different key orderings, say d2 = {'x': 3, 'b':7, 'c': 3, 'a':9}, consistent results are still given.