How to add values to existing dictionary key Python

Question

I am trying to create a function that takes in four parameters: A keyname, start time, end time, and then a dictionary. I have to create a tuple out of the start time and end ti

Answer 1

Try this:

def insertIntoDataStruct(name,startTime,endTime,aDict):
    if not name in aDict:
        aDict[name] = [(startTime,endTime)]
    else:
        aDict[name].append((startTime,endTime))

Now define your dict:

courses = {}

and start adding the courses:

insertIntoDataStruct("CS 2316", "1505", "1555", courses)
insertIntoDataStruct("CS 2316", "1405", "1455", courses)
insertIntoDataStruct("CS 2316", "1305", "1355", courses)
insertIntoDataStruct("CS 4400", "1405", "1455", courses)
insertIntoDataStruct("CS 4400", "1605", "1655", courses)

Answer 2

You might want to use a defaultdict instead.

from collections import defaultdict

def insertIntoDataStruct(name,startTime,endTime,aDict):
    aDict[name].append((int(startTime), int(endTime)))
    return aDict

courses = defaultdict(list)
courses = insertIntoDataStruct("CS 2316", "1505", "1555", courses)
courses = insertIntoDataStruct("CS 2316", "1405", "1455", courses)
courses = insertIntoDataStruct("CS 2316", "1305", "1355", courses)
courses = insertIntoDataStruct("CS 4400", "1405", "1455", courses)
courses = insertIntoDataStruct("CS 4400", "1605", "1655", courses)


print courses == {'CS 2316': [(1505, 1555), (1405, 1455), (1305, 1355)], 'CS 4400': [(1405, 1455), (1605, 1655)]}
print courses

Perhaps you don't even need a function.

from collections import defaultdict
courses = defaultdict(list)
courses["CS 2316"].append((int("1505"), int("1555")))
courses["CS 2316"].append((int("1405"), int("1455")))
courses["CS 2316"].append((int("1305"), int("1355")))
courses["CS 4400"].append((int("1405"), int("1455")))
courses["CS 4400"].append((int("1605"), int("1655")))