[Python] 函数

 1 def nth_power(exponent):
 2     def exponent_of(base):
 3         return base ** exponent
 4     return exponent_of
 5 
 6 square = nth_power(2)
 7 cube = nth_power(3)
 8 
 9 print(square(2))
10 print(cube(3))

1 [(lambda x:x*x)(x) for x in range(10)]

1 l = [(1,20),(3,0),(9,10),(2,-1)]
2 l.sort(key=lambda x:x[1])
3 print(l)

 1 import random
 2 
 3 class BingoCage:
 4     def __init__(self, items):
 5         self._items = list(items)
 6         random.shuffle(self._items)
 7     def pick(self):
 8         try:
 9             return self._items.pop()
10         except IndexError:
11             raise LookupError(‘pick from empty BingoCage‘)
12     def __call__(self):
13         return self.pick()
14 
15 bingo = BingoCage(range(5))
16 bingo.pick()

1 # map函数
2 def factorial(n):
3     return 1 if n < 2 else n * factorial(n-1)
4 
5 fact = factorial
6 list(map(fact,range(10)))

1 list(map(fact, filter(lambda n:n%2,range(6))))

1 from functools import reduce 
2 reduce(lambda x, y: x+y, [1,2,3,4,5])