“用途"的含义和区别是什么?和“重新绑定"一个变量? [英] What are the meanings and differences between "uses" and "rebinds" a variable?

问题描述

简而言之，来自 Python:

From Python in a Nutshell:

避开全球

如果函数体只使用一个全局变量，则不要使用全局变量变量(包括改变绑定到它的对象变量，当对象是可变的时).

Never use global if the function body just uses a global variable (including mutating the object bound to that variable, when the object is mutable).

仅在以下情况下使用全局语句函数体重新绑定一个全局变量(通常通过分配给变量的名称).

Use a global statement only if the function body rebinds a global variable (generally by assigning to the variable’s name).

使用"和重新绑定"变量的含义和区别是什么?

What are the meanings and differences between "uses" and "rebinds" a variable?

改变绑定到变量的对象"是使用"还是重新绑定"变量?为什么?

Is "mutating the object bound to a variable" "uses" or "rebinds" the variable? Why?

推荐答案

Mutate"和bind"/rebind"是两个互斥的操作.变异改变了一个对象，而绑定改变了一个名字.

"Mutate" and "bind"/"rebind" are two mutually exclusive operations. Mutating changes an object, whereas binding changes a name.

这是绑定:

a = []

这是变异:

a.append(None)

使用"意味着访问绑定到一个名称的现有对象，无论是为了读取还是为了改变.

"Using" means accessing the existing object bound to a name, whether for reading or for mutation.

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