<pre><code>>>> def f():
... return {'a' : 1, 'b' : 2}
...
>>> def g():
... return dict(a=1, b=2)
...
>>> g()
{'a': 1, 'b': 2}
>>> f()
{'a': 1, 'b': 2}
>>> import dis
>>> dis.dis(f)
2 0 BUILD_MAP 0
3 DUP_TOP
4 LOAD_CONST 1 ('a')
7 LOAD_CONST 2 (1)
10 ROT_THREE
11 STORE_SUBSCR
12 DUP_TOP
13 LOAD_CONST 3 ('b')
16 LOAD_CONST 4 (2)
19 ROT_THREE
20 STORE_SUBSCR
21 RETURN_VALUE
>>> dis.dis(g)
2 0 LOAD_GLOBAL 0 (dict)
3 LOAD_CONST 1 ('a')
6 LOAD_CONST 2 (1)
9 LOAD_CONST 3 ('b')
12 LOAD_CONST 4 (2)
15 CALL_FUNCTION 512
18 RETURN_VALUE
</code></pre>
<p>dict()显然是C内置的。一个真正聪明或专注的人(不是我)可以看看翻译源代码,告诉你更多。我只是想炫耀一下dis.dis。:)</p>