Python解包时不允许注释变量类型
Python does not allow annotating the types of variables when unpacking
PEP 526 表示如下：
Note that, although the syntax does allow tuple packing, it does not allow one to annotate the types of variables when tuple unpacking is used.
为什么python解包时不支持变量的类型注解？
PS。我必须先注释类型，然后再进行拆包，这很好，只是在拆包时进行注释会更整洁。
PEP 526 的 Rejected/Postponed Proposals section 中有一些关于此的信息：
Allow type annotations for tuple unpacking: This causes ambiguity: it's not clear what this statement means:
x, y: T
Are x and y both of type T, or do we expect T to be a tuple type of two items that are distributed over x and y, or perhaps x has type Any and y has type T? (The latter is what this would mean if this occurred in a function signature.) Rather than leave the (human) reader guessing, we forbid this, at least for now.
该评论似乎暗示最终可能会提出一个更简单的语法的提案，该语法不容易被误解。现在，我们不得不单独注释元组的类型。
PEP 526 表示如下：
Note that, although the syntax does allow tuple packing, it does not allow one to annotate the types of variables when tuple unpacking is used.
为什么python解包时不支持变量的类型注解？ PS。我必须先注释类型，然后再进行拆包，这很好，只是在拆包时进行注释会更整洁。
PEP 526 的 Rejected/Postponed Proposals section 中有一些关于此的信息：
Allow type annotations for tuple unpacking: This causes ambiguity: it's not clear what this statement means:
x, y: TAre x and y both of type T, or do we expect T to be a tuple type of two items that are distributed over x and y, or perhaps x has type Any and y has type T? (The latter is what this would mean if this occurred in a function signature.) Rather than leave the (human) reader guessing, we forbid this, at least for now.
该评论似乎暗示最终可能会提出一个更简单的语法的提案，该语法不容易被误解。现在，我们不得不单独注释元组的类型。