开箱：[x，y]，（x，y），x，y-有什么区别？

没有区别。无论您使用哪种 语法 序列，都将生成相同的字节码。

>>> def f():...   return 0, 1...>>> import dis>>> dis.dis('[a,b] = f()')  10 LOAD_NAME     0 (f)   2 CALL_FUNCTION 0   4 UNPACK_SEQUENCE          2   6 STORE_NAME    1 (a)   8 STORE_NAME    2 (b)  10 LOAD_ConST    0 (None)  12 RETURN_VALUE>>> dis.dis('(a,b) = f()')  10 LOAD_NAME     0 (f)   2 CALL_FUNCTION 0   4 UNPACK_SEQUENCE          2   6 STORE_NAME    1 (a)   8 STORE_NAME    2 (b)  10 LOAD_ConST    0 (None)  12 RETURN_VALUE>>> dis.dis('a, b = f()')  10 LOAD_NAME     0 (f)   2 CALL_FUNCTION 0   4 UNPACK_SEQUENCE          2   6 STORE_NAME    1 (a)   8 STORE_NAME    2 (b)  10 LOAD_ConST    0 (None)  12 RETURN_VALUE

在每种情况下，您只需调用

f

UNPACK_SEQUENCE

a

b

即使您想证明字节码是CPython的实现细节，链式分配的定义 也不是 。给定

x = [a, b] = f()

含义与

tmp = f()x = tmp[a, b] = tmp

x

f()

[a, b]

最后，这是赋值语句的语法：

assignment_stmt ::=  (target_list "=")+ (starred_expression | yield_expression)target_list     ::=  target ("," target)* [","]target          ::=  identifier          | "(" [target_list] ")"          | "[" [target_list] "]"          | attributeref          | subscription          | slicing          | "*" target

可以说，

"[" [target_list] "]"