Python学习笔记（八）

1.函数就是程序中可重复使用的程序段
用关键字“def”来定义，给一段程序起一个名字，用这个名字来执行一段程序，反复使用

# coding:utf-8
def say_hi():
    print("hi!")
say_hi()

#参数Function
def print_sum_two(a,b):
    c = a + b
    print(c)
print_sum_two(3, 6)

#传入字符串
def hello_some(str):
    print("Hello "+ str + "!")
hello_some("China")

#有返回值的function
def repeat_str(str,times):
    repeated_strs = str * times
    return repeated_strs
repeated_string = repeat_str("Happy Birthday", 4)
print(repeated_string)

#全局变量与局部变量
x = 60

def fao(x):
    print("x is " + str(x))
    x = 3
    print("change local x to " + str(x))
fao(x)
print("x is still " + str(x))

#global 用法
y = 60

def foo():
    global y
    print("y is " + str(y))
    y = 3
    print("change local y to " + str(y))
foo()
print("x is " + str(y))

2.默认参数、关键字参数、VarArgs参数

#默认参数
def repeat_str1(str,times=1):
    repeated_strs = str * times
    return repeated_strs
repeated_string = repeat_str1("Happy Birthday")
print(repeated_string)

#关键字参数
#f(a,b =2)#合法
#f(a =2 ,b)#不合法

#关键字参数
def func(a,b =4,c =8):
    print("a is",a,"b is",b,"c is",c)
func(13, 17)
func(125,c=26)
func(c=28,a=5)

#VarsArgs参数
def print_paras(fpara,*nums,**word):
    print("fpara:"+str(fpara))
    print("nums"+ str(nums))
    print("words"+ str(word))
print_paras("Hello",1,3,5,7,word = "python", another_word = "java")