CS 61A Summer 2018 Live Lecture 17: Mutable Functions about learning_list HOT 12 OPEN

Mutable Functions in Python

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Mutable Functions in Scheme

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Why don't we need nonlocal in JS or Scheme?

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They do more than just return a value, they change the environment.

最实用的纯函数描述：

• 输入不变时，输出也不可变
• 运行结束时，除了返回的函数值之外，对 environment 没有任何其他改变

from learning_list.

= 的本质是改变，而不是赋值。如果非要说赋值，那就是重新赋值。
在 Python 中，= 要么是绑定，要么是重新绑定，默认在当前作用域下进行。而当前作用域下的所需的所有 name 已经被事先计算出来。

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