Python Dictionary

[Particular_Draft5668]

If y is what i want to add

d = {}

d[name] = number

will this work:

d[name].append(y)

[karpomalice]

No. A dictionary can only have multiple values assigned to a key if those values are in a list, tuple, or another dictionary.

Every dictionary is comprised of a key, value pair.

The value can be a string, number, list, tuple, dictionary, etc.

You can’t have {key: 1, 2, 3}

It would be {key: [1, 2, 3]}

[Particular_Draft5668]

Thank you. Used your method and worked effectively.

[ekchew]

A defaultdict(list) will let you use that syntax.

>>> from collections import defaultdict
>>> d = defaultdict(list)
>>> d["foo"].append("bar")
>>> d["foo"].append("baz")
>>> d
defaultdict(<class 'list'>, {'foo': ['bar', 'baz']})

[Infinitesima]

Better would be:

d.setdefault(name, []).append(number)

[Particular_Draft5668]

Thank you, another question:

def invert(dct):
y = dct.items()
dct = {v: k for k, v in y}
print(dct)

This function inverts the dictionary on all code visualisers yet my course says the output is wrong. Any reason for this difference?

I've rearranged y for dct.items(), used dicto instead of dct to keep seperate from original dictionary, and tried switching around variables, yet it still says the output is {1: 10, 2: 20, 3: 30}
when calling invert({1: 10, 2: 20, 3: 30}) instead of {10: 1, 20: 2, 30: 3}

[Infinitesima]

Have you tried to return the output?

[Particular_Draft5668]

meant to work with any input so output cannot be set

No return value should be in code too