How to change a value in an array in Python?

Question

Python

There is a dictionary and an array:
list = [{"1": [1, 2]}]

And how to add a value to the list dictionary?
Tried doing .update and += and = : list["1"].update(3) and list["1"] += [3] and list["1"] = [3], but it worked:
[{ "1": [1, 2, [], 3]}]
Please help.

Answer 1

change value in array

add value to list dictionary

You need to decide whether you want to change the value in the list, or add a key to the dictionary
list[0]['1'].append(3)

Answer 2

It's not entirely clear what you need to end up with:

lst = [{"1": [1, 2]}]   # называть переменную list - плохая практика
lst[0]['1'].append(3)
print(lst)
# [{'1': [1, 2, 3]}]

lst[0]['2'] = [4, 5]
print(lst)
# [{'1': [1, 2, 3], '2': [4, 5]}]