Question

I have created a dictionary of either {'username': 'date'} or {'date': 'username'} (I can change the order of the key: value pair to whichever I want). To set the values I need to say…

{'Jacob Rasnip': 'Apr', 'Andrew Alexander': 'Apr', 'Jacob Rasnip': 'May'}

or the opposite…

{'Apr': 'Jacob Rasnip'}

I have about 1500 of dictionary values, all users with different months assigned to them or months assigned with users.

I want a way to iterate through a dictionary of keys and values, and figure out which month was the first month a customer appeared. I also want to find the last month that the customer appeared.

Could someone please offer advice as to the best way to achieve this.

Answer 1

You said.

Could I have each name (as a key) have multiple values? Currently I’m combining two lists (one of names, the other of dates) like this: testdict = dict(zip(name, date))

No, but you can combine those values in a way that looks like unutbu’s answer.

import collections
data = collections.defaultdict(list)

for n, d in zip(name, date):
    data[n].append(d)