python_形参、实参

#参数：形参、实参
'''
def display_message(title):

print("My favourite book is %s" %title)

#return 0

#display_message('alice in Wonderland'.title())

def describe_pet(pet_name,animal_type="dog"):
"""显示宠物信息"""
print("My "+animal_type+"'s name is "+pet_name)

describe_pet(pet_name="Who") #该处实参使用形参的默认值，animal_type = dog
describe_pet(pet_name="Who",animal_type="cat") #animal_type提供了实参，Python将忽略形参的默认值

#describe_pet() #实参不匹配，没有指定任何参数，实参个数必须与形参个数一致

 

def null(x,y):
print(x)
print(y)

null(1,2)
print(display_message("mo"))

'''

#返回值
#让返回值变为可选的，只需要把可选的形参放在最后，并指定一个默认值——空字符串。但是在传实参时，位置与形参一一对应。
'''
def full_name(first_name,last_name,middle_name =''):
full_name = first_name+' '+middle_name+' '+last_name

return full_name.title()
name= full_name("liu","qian",'01')
print(name)
'''

#返回字典
'''
def info(name,age ,sex):
"""返回一个字典，其中包含有关一个人的信息"""
message = {'name':name,'age':age,'sex':sex}
return message

b=info("Monica",24,"F")
print(b)

def test1(**kwargs):
print(kwargs)

test1(name = "Lee",age = 24)
'''
#结合函数和while循环
def full_name(first_name,last_name):
full_name = first_name+' '+last_name
return full_name.title()

exit_flag = False
while not exit_flag:
print("Please input your name:","\n","(enter 'q' at any time to quit)")
f_name = input("First_name:") #输入first_name,last_name
if f_name == 'q':
#exit_flag = True
break

l_name = input("Last_name:")
if l_name == 'q':
exit_flag == 'q'
name = full_name(f_name,l_name) #调用方法传入实参
print(name)
----------------------------------------------------
def data(host,port=3396):
pass

data()
'''
#默认参数特点：调用函数时，默认参数非必传
#用途：1.默认安装值 2.数据库的端口号

 

'''
def test(**kwargs):
print(kwargs)
print(kwargs['name'])

test(name = 'Alex',age =22)
test(**{'name':'Alex','age':22})
'''

#*args接收N个位置参数，不能接收关键字参数，转换成元组的形式。
#kwargs把N个关键字参数，转换成字典的方式
def test2(name,hobby='tesla',*args,**kwargs):
info = {}
info['name']=name
info['hobby']=hobby
for key,value in kwargs.items():
info[key]=value
# print(name)
# print(kwargs)
return info

user_info =test2('alex','blue','apple',age=23,sex="f")
print(user_info)