python笔记基础--函数（5）

函数定义

def greet_user(): #定义函数
    #显示简单问候语
    print("Hello World!")

greet_user()#调用函数

Hello World!

向函数传递信息

def greet_user(username): #定义函数
    #显示简单问候语
    print(f"Hello,{username.title()}")

greet_user('dylan')#调用函数

Hello,Dylan

形参：username，函数完成工作所需的信息

实参：’dylan’，调用函数时传递给函数的信息

def describe_pet(animal_type, pet_name):
    #显示宠物信息
    print(f"I have a {animal_type}.")
    print(f"My {animal_type}'s name is {pet_name.title()}.")

describe_pet('hamster', 'harry')

I have a hamster.

My hamster's name is Harry.

多次

调用

函数

describe_pet('hamster', 'harry')
describe_pet('cat', '包子')

I have a hamster.

My hamster's name is Harry.

I have a cat.

My cat's name is 包子.

describe_pet(animal_type='hamster', pet_name='harry')
describe_pet(pet_name='包子', animal_type='cat')

I have a hamster.

My hamster's name is Harry.

I have a cat.

My cat's name is 包子.

def describe_pet(pet_name='Dylan',animal_type='dog'):
    ……
describe_pet()

I have a dog.

My dog's name is Dylan.

def describe_pet(pet_name,animal_type='dog'):

……

describe_pet(pet_name='harry')

describe_pet(pet_name='harry',animal_type='cat')

I have a dog.

My dog's name is Harry.

I have a cat.

My cat's name is Harry.

如果调用未说明实参给谁，则优先给没有默认值的那一个。

如果调用给了所有实参，则按照顺序依次赋值

注：不可以def describe_pet(pet_name='Ann',animal_type)，默认值要放到最后，不能放到前面

def get_formatted_name(first_name,last_name):
    full_name = f"{first_name} {last_name}"
    return full_name.title()
musician = get_formatted_name('jem','harry')
print(musician)

Jem Harry

def get_formatted_name(first_name,last_name,middle_name=''):
    if middle_name:
        full_name = f"{first_name} {middle_name} {last_name}"
    else:
        full_name = f"{first_name} {last_name}"
    return full_name.title()
A= get_formatted_name('jem','harry')
print(A)
B = get_formatted_name('jem','harry','lee')
print(B)

Jem Harry

Jem Lee Harry

def buile_person(first_name,last_name):
    person = {'first':first_name, 'last':last_name}
    return person
A=buile_person('jem','herry')
print(A)

{'first': 'Jem', 'last': 'herry'}

def buile_person(first_name,last_name,age=None):
    person = {'first':first_name, 'last':last_name}
    if age:
        person['age']=age
    return person
A=buile_person('jem','herry',age=99)
print(A)

{'first': 'jem', 'last': 'herry', 'age': 99}

def buile_person(first_name,last_name):
    full_name = f"{first_name} {last_name}"
    return full_name

while True:
    print(f"请告诉我你的名字：")
    print(f"(直到用户输入q时退出循环)")
    f_name = input("first name:")
    if f_name == 'q':
        break
    l_name = input("last name:")
    if l_name == 'q':
        break

formatted_name = buile_person(f_name,l_name)
print(f"\nHello,{formatted_name}")

请告诉我你的名字：

(直到用户输入q时退出循环)

first name:ann

last name:jee

请告诉我你的名字：

(直到用户输入q时退出循环)

first name:q

Hello,q jee

函数

遍历列表

def greet_users(names):
    #向列表中的每位用户发出简单的问候
    for name in names:
        msg = f"Hello,{name.title()}!"
        print(msg)

usernames = ['Ann','ty','mar']
greet_users(usernames)

Hello,Ann!

Hello,Ty!

Hello,Mar!

在函数中

修改列表

#1.创建一个列表，其中包含一些要打印的设计
un_designs = ['phone','robot','TV']
com_models = []
#模拟打印每个设计，直到没有未打印的设计为止
#打印每个设计后，将其移到列表com_models中
while un_designs:
    cur_designs = un_designs.pop() #删除列表末尾
    print(f"Printing moder:{cur_designs}")
    com_models.append(cur_designs) #末尾添加

#显示打印好的所有模型
print("\nThe following models have been printed:")
for com_model in com_models:
    print(com_model)

Printing moder:TV

Printing moder:robot

Printing moder:phone

The following models have been printed:

TV

robot

phone

def print_models(un_designs,com_models):
        while un_designs:
        cur_designs = un_designs.pop()
        print(f"Printing moder:{cur_designs}")
        com_models.append(cur_designs)
def show_com_models(com_models):
    print("\nThe following models have been printed:")
    for com_model in com_models:
        print(com_model)

un_designs = ['phone','robot','TV']
com_models = []

print_models(un_designs,com_models)
show_com_models(com_models)

禁止函数

修改列

print_models(un_designs[:],com_models)

切片

def make_pizza(*toppings):
    print(toppings)
make_pizza('pepperoni')
make_pizza('peppers','mushrooms','sugar')

('pepperoni',)

('peppers', 'mushrooms', 'sugar')

def make_pizza(*toppings):
    print("\nThe toppings:")
    for topping in toppings:
        print(f"- {topping}")
make_pizza('pepperoni')
make_pizza('peppers','mushrooms','sugar')

The toppings:

- pepperoni

The toppings:

- peppers

- mushrooms

- sugar

def make_pizza(size, *toppings):
make_pizza(16,'pepperoni')
make_pizza(20,'peppers','mushrooms')

The 16 toppings:

- pepperoni

The 20 toppings:

- peppers

- mushrooms

def build_p(first, last, **user_info):
    """创建一个字典，包含关于用户的一切"""
    user_info['first_name'] = first
    user_info['last_name'] = last
    return user_info

user_p = build_p('abc','def',location='prt',f='j')
print(user_p)

{'location': 'prt',

 'f': 'j',

'first_name': 'abc',

'last_name': 'def'}

pizza.py

def make_pizza(size,*toppings):
    print(f"The {size} topping:")
    for topping in toppings:
        print(f"---{topping}")

making_pizza.py

import pizza  #导入模块pizza.py

pizza.make_pizza(16,'sugar')
pizza.make_pizza(43,'green','sugar')

The 16 topping:

---sugar

The 43 topping:

---green

---sugar

making_pizza.py

导入pizza.py中的make_pizza的函数

from pizza import make_pizza