day-3 函数

def write_file(filename,content):#filename，content都是形式参数
    with open(filename,'a+',encoding='utf-8') as fw:
        fw.write(content+'
')


def read_file(filename):
    with open(filename,encoding='utf-8') as fr:
        result = fr.read()
        return result#返回值，什么时候需要返回值，要看具体函数的作用
    #函数里面遇到return,函数立即结束

write_file('a.txt','aaaaaa')
rea = read_file('a.txt')#a.txt是实际参数
print(rea)

def more():
    name = 'xiaoming'
    age = 18
    score = 99
    return name,age,score
#多个返回值
# 方法1
result = more()
print(result)
# 方法2
name,age,score = more()# 用3个值来接收
print(name)
print(age)
print(score)

# 默认值参数
def user(name,sex='女'):
    print(name,sex)
user('xiaobai','男')
user('xiaolan')