dataclasses-vs-typeddict.py

import dis
from dataclasses import dataclass
from typing import TypedDict

@dataclass
class MyDataclass:
    field1: str
    field2: int

class MyTypedDict:
    field1: str
    field2: int

def my_dataclass():
    a = MyDataclass('a', 0)
    a.field1 = 'b'
    a.field2 = 1
    print(a.field1, a.field2)

def my_typeddict():
    a = {'field1': 'a', 'field2': 0}
    a['field1'] = 'b'
    a['field2'] = 1
    print(a['field1'], a['field2'])

my_dataclass()
my_typeddict()
print("============================")
dis.dis(my_dataclass)
print("============================")
dis.dis(my_typeddict)

out.txt

b 1
b 1
============================
 15           0 LOAD_GLOBAL              0 (MyDataclass)
              2 LOAD_CONST               1 ('a')
              4 LOAD_CONST               2 (0)
              6 CALL_FUNCTION            2
              8 STORE_FAST               0 (a)

 16          10 LOAD_CONST               3 ('b')
             12 LOAD_FAST                0 (a)
             14 STORE_ATTR               1 (field1)

 17          16 LOAD_CONST               4 (1)
             18 LOAD_FAST                0 (a)
             20 STORE_ATTR               2 (field2)

 18          22 LOAD_GLOBAL              3 (print)
             24 LOAD_FAST                0 (a)
             26 LOAD_ATTR                1 (field1)
             28 LOAD_FAST                0 (a)
             30 LOAD_ATTR                2 (field2)
             32 CALL_FUNCTION            2
             34 POP_TOP
             36 LOAD_CONST               0 (None)
             38 RETURN_VALUE
============================
 21           0 LOAD_CONST               1 ('a')
              2 LOAD_CONST               2 (0)
              4 LOAD_CONST               3 (('field1', 'field2'))
              6 BUILD_CONST_KEY_MAP      2
              8 STORE_FAST               0 (a)

 22          10 LOAD_CONST               4 ('b')
             12 LOAD_FAST                0 (a)
             14 LOAD_CONST               5 ('field1')
             16 STORE_SUBSCR

 23          18 LOAD_CONST               6 (1)
             20 LOAD_FAST                0 (a)
             22 LOAD_CONST               7 ('field2')
             24 STORE_SUBSCR

 24          26 LOAD_GLOBAL              0 (print)
             28 LOAD_FAST                0 (a)
             30 LOAD_CONST               5 ('field1')
             32 BINARY_SUBSCR
             34 LOAD_FAST                0 (a)
             36 LOAD_CONST               7 ('field2')
             38 BINARY_SUBSCR
             40 CALL_FUNCTION            2
             42 POP_TOP
             44 LOAD_CONST               0 (None)
             46 RETURN_VALUE