[Cookbook] Chapter 7: Functions

7.1 function accepts any number of parameters

def get_attr(first, *args):
    print(*args)

7.2 Zhi function accepts keyword arguments

def get_attr(first, *args, k, **kwargs):
    print(k)


get_attr(1, 'halo', 'halo2', k=2, w=3, d=4)

7.3 to the function parameter increases meta-information

def add(x: int, y: int) -> int:
    return x + y

7.4 function returns a plurality of values

def add():# 返回元组
    return 1, 2, 3


a, b, _ = add() # 元组拆包

7.5 -defined functions have default parameters

def add(i=4):
    return 1, 2, i

7.6 define anonymous functions

names = ['David Beazley', 'Brian Jones', 'Raymond Hettinger', 'Ned Batchelder']
sorted(names, key=lambda name: name.split()[-1].lower())

7.7 anonymous function captures variable values

Rather than capture the definition at runtime