第五讲：函数

# -*- coding:utf-8 -*-
#
# 函数
# 无参函数
def print_hello():
    print ("hello")
print_hello()
# 带参函数
def print_str(s):
    print (s)
    return s * 2
print_str("fuck")  # fuck
print (print_str("fuck"))  # fuckfuck
# 带默认参数的函数
def print_default(s="hello"):
    print (s)
print_default()     # hello
print_default("default")    # default
# 不定长参数
def print_args(s, *arg):
    print (s)
    for a in arg:
        print (a)
    return
print_args("hello")
print_args("..hello", "..world", "..1")
# 参数次序可以变
def print_two(a, b):
    print (a,b)
print_two(1, 2)
print_two(a="a", b="b")
print_two(b="b", a="a")