Why do we need a dict.update() method in python instead of just assigning the values to the corresponding keys?

I have been working with dictionaries that I have to modify within different parts of my code. I am trying to make sure if I do not miss anything about there is no need for dict_update() in any scenario.

So the reasons to use update() method is either to add a new key-value pair to current dictionary, or update the value of your existing ones.

But wait!?

Aren’t they already possible by just doing:

>>>test_dict = {'1':11,'2':1445}
>>>test_dict['1'] = 645
>>>test_dict
{'1': 645, '2': 1445}
>>>test_dict[5]=123
>>>test_dict
{'1': 645, '2': 1445, 5: 123}

In what case it would be crucial to use it ? I am curious.

Many thanks

>Solution :

d.update(n) is basically an efficient implementation of the loop

for key, value in n.items():
    d[key] = value

But syntactically, it also lets you specify explicit key-value pairs without building a dict, either using keyword argumetns

d.update(a=1, b=2)

or an iterable of pairs:

d.update([('a', 1), ('b', 2)])