《Python cookbook》读书笔记📒

[wbcs]

第七章 函数

new

• *args 必须作为最后一个 位置参数，其后的所有参数都会被所谓关键字参数。**kwargs 必须作为最后一个 参数:

def func(a, b, *args, c, d, **kwargs):
    pass

• 函数返回多个值，其实就是返回了一个 tuple 而已（实际上创建tuple的不是()而是,）
• 给 mutable 变量赋值默认参数时，应当使用 None ，而不是[], (), {}
• 协程（感觉像js里的generator）:

def fn():
    prev_args = None
    while True:
        args = yield prev_args
        print('args: ', args)
        prev_args = args

var = fn()
next(var)
print(var.send(1))
print(var.send(2))
print(var.send(3))
'''
args:  1
1
args:  2
2
args:  3
3
'''

API

• functools.partial
• 获取对应层级(0为当前stack)的 context: sys._getframe(1).f_locals

import sys

def split_callable_and_others():
    locals = sys._getframe(1).f_locals
    callable_locals = {}
    others = {}
    for key, value in locals.items():
        if callable(value):
            callable_locals.update({key: value})
        else:
            others.update({key: value})
    return callable_locals, others

def test():
    def i_am_callable():
        return 'oh yes'

    fuck = 'bitch'
    # ({'i_am_callable': <function test.<locals>.i_am_callable at 0x7ffb2d13b790>}, {'fuck': 'bitch'})
    print(split_callable_and_others())

if __name__ == '__main__':
    test()

• callable