链函数

链函数: chain函数串联a和b，兼顾内存效率同时写法更加优雅

from itertools import chain

a = [1, 3, 5, 0]
b = {'a': 1, 'b': 2}

# 演示一: 
for i in chain(a, b):
    print(i, end=' ')  # 1 3 5 0 a b 1
print()

# 演示二: 
print(b.values())  # dict_values([1, 2])
for i in chain(a, b.values()):
    print(i, end=' ')  # 1 3 5 0 1 2
print()

# 演示三:
c = '2,4,6'
for i in chain(a, c):
    print(i, end=' ')  # 1 3 5 0 2 , 4 , 6