python笔记6 函数

##关键字def自定义函数
def greet_user(username):  #username 为形参
print('Hello,'+username.title()+'!')
greet_user('Curry') #'curry'为实参

##传递实参##----函数的调用：位置实参，关键字实参和默认值
#位置实参(可根据需要调用函数任意次)
def describe_pets(animal_type,pet_name):
"""显示宠物的信息"""  #描述函数做什么的
print('The '+animal_type.title()+"'s name is "+pet_name.title())
describe_pets('dog','harry')#注意实参顺序
#
def describe_pets(animal_type,pet_name):
"""显示宠物的信息"""  #描述函数做什么的
print('The '+animal_type.title()+"'s name is "+pet_name.title())

message={}
while True:
animal=input("Enter the animal's type:")
name=input("Enter the pet's name:")
prompt=input("You can enter 'end' to end the program,or enter any key to continue:")
message[animal]=name
if prompt=='end':
break

for animal,name in message.items():
describe_pets(animal,name)
#---------
#关键字实参（无需注意实参的顺序）
def describe_pets(animal_type,pet_name):
print('The '+animal_type.title()+"'s name is "+pet_name.title())
describe_pets(pet_name='harry',animal_type='dog')
#默认值
def describe_pets(pet_name,animal_type='dog'):#设置默认值的实参在后
print('The '+animal_type.title()+"'s name is "+pet_name.title())
describe_pets('harry')

def describe_pets(pet_name,animal_type='dog'):
print('The '+animal_type.title()+"'s name is "+pet_name.title())
describe_pets('Tom','cat') #提供实参将忽略默认值


##返回值 return语句
#返回简单值
def user_name(first_name,last_name):
full_name=first_name+' '+last_name
return full_name.title()
user=user_name('Tom','curry')
print(user)
#实参变成可选的
def user_name(first_name,last_name,middle_name=''):
if middle_name:
full_name=(first_name+' '+middle_name+" "+last_name)
return full_name.title()
else:
full_name=first_name+last_name
return full_name.title()
user=user_name('Tom','curry')
print(user)
user=user_name('Tom','curry','tee')
print(user)
#返回字典
def personal_imformation(name,age):
person={'name':name,'age':age}
return person
user=personal_imformation('chen','20')
print(user)
##结合使用函数和while循环
def personal_imformation(name,age):
person={'name':name,'age':age}
return person
while True:
message_name=input('Enter your name:')
message_age=input('Enter your age:')
user=personal_imformation(message_name,message_age)
print(user)
prompt=input("Enter 'end' to end the program,or enter any key to continue:")
if prompt=='end':
break

##传递列表
def greet_user(names):
"""向列表中的每位用户都发出简单的问候"""
for name in names:
print('Hello,'+name.title()+'!')
usernames=['curry','chen','hu','harry','tom']
greet_user(usernames)
#
def greet_user(names):
"""向列表中的每位用户都发出简单的问候"""
for name in names:
print('Hello,'+name.title()+'!')
usernames=[]
while True:
name_message=input('Enter your name:')
usernames.append(name_message)
prompt=input("Enter 'end' to end the program:")
if prompt=='end':
break
greet_user(usernames)

#在函数中修改列表(定义两个函数)
def print_models(unprinted_designs,completed_models):
"""打印每个设计，并将其移到列表completedd_models中"""
while unprinted_designs:
current_design=unprinted_designs.pop()
print("printing model: "+current_design.title())
completed_models.append(current_design)

def show_completedd_models(completed_models):
"""显示所有打印完的模型"""
print('\nThe following models have been printed:')
for completed_model in completed_models:
print(completed_model)

unprinted_designs=['case','robot','derbo','range']
completed_models=[]
print_models(unprinted_designs,completed_models)
show_completedd_models(completed_models)

#禁止函数修改列表 （切片表示法[:]）传递副本
def print_models(unprinted_designs,completed_models):
"""打印每个设计，并将其移到列表completedd_models中"""
while unprinted_designs:
current_design=unprinted_designs.pop()
print("printing model: "+current_design.title())
completed_models.append(current_design)

def show_completedd_models(completed_models):
"""显示所有打印完的模型"""
print('\nThe following models have been printed:')
for completed_model in completed_models:
print(completed_model)

unprinted_designs=['case','robot','derbo','range']
completed_models=[]
print_models(unprinted_designs[:],completed_models)####将列表副本传递给函数
show_completedd_models(completed_models)

print(unprinted_designs)##打印原列表确定没变

##传递任意数量的实参
def make_pizza(*toppings):
"""打印顾客点的所有配料"""
print("\nMaking a pizza with the following toppings:")
for topping in toppings:
print(topping)

make_pizza('pepperoni')
make_pizza('mushroom','green peppers','extra cheese')

#结合使用位置实参和任意数量的实参
def make_pizza(size,*toppings):
"""打印顾客点的所有配料"""
print("\nMaking "+str(size)+" pizza with the following toppings:")
for topping in toppings:
print(topping)

make_pizza(12,'pepperoni')
make_pizza(16,'mushroom','green peppers','extra cheese')

##使用任意数量的关键字实参
def build_profile(first,last,**user_info):#**user_info 让python创建一个名为user_info的空字典
"""创建一个字典，其中包含有关用户的一切"""
profile={}
profile["first_name"]=first
profile["last_name"]=last
for key,value in user_info.items():
profile[key]=value
return profile ##将profile字典返回给函数调用
user_profile=build_profile('albert','dsafg',
   location='princeton',
   field='physics')
print(user_profile)

####将函数存储在模块中
##导入整个模块
"""def make_pizza(*toppings):
print("\nMaking a pizza with the following toppings:")
for topping in toppings:
print(topping)"""  #一个名为pizza.py的文件

import pizza   #让python打开pizza.py,并将其所有函数复制到这个程序中

pizza.make_pizza(16,"pepperoni")
pizza.make_pizza(12,"pepperoni",'green pepper','extra cheese')

##导入特定的函数
#from 文件名 import 函数名    （导入特定函数）
#from 文件名 import 函数1,函数2,函数3 （根据需要导入任意数量的函数）

##使用 as 给函数指定别名
from pizza import make_pizza as mp
mp(16,"pepperoni")
mp(12,"pepperoni",'green pepper','extra cheese')

##使用 as 给模块指定别名
import pizza as p
p.make_pizza(16,"pepperoni")
p.make_pizza(12,"pepperoni",'green pepper','extra cheese')

##导入模块中的所有函数 （无需使用句点表示法） 【尽量不用这种方法】
from pizza import *
make_pizza(16,"pepperoni")
make_pizza(12,"pepperoni",'green pepper','extra cheese')