定义函数

#定义函数
def greet_user():print("Hello~")#调用函数
greet_user()#向函数传递信息
def print_user(username):print(f"Hello~{username}")print_user('Jesse')

传递实参数

#位置实参
def describe_pet(animal_type, pet_name):print(f"I have a {animal_type}")print(f"My {animal_type}'s name is {pet_name.title()}")describe_pet('hamster', 'harry')#关键字实参数&默认值
def describe_peet(animal_type='haster', pet_name='harry'):print(f"I have a {animal_type}")print(f"My {animal_type}'s name is {pet_name.title()}")describe_peet()
describe_peet(pet_name='Zhangsan', animal_type='human')

返回值

#返回简单值
def get_formatted_name(first_name, last_name):full_name = f"{first_name} {last_name}"return full_name.title()musician = get_formatted_name('jimi', 'hendrix')
print(musician)#让实参数可选
def formatted_name(first_name, last_name, middle_name=''):full_name = f"{first_name} {middle_name} {last_name}"return full_name.title()musician = formatted_name('jimi', 'hendrix')
print(musician)
musician = formatted_name('jimi', 'hendrix', 'lee')
print(musician)

传递列表

#在函数中修改列表
def print_models(unprinted_designs, completed_models):while unprinted_designs:current_design = unprinted_designs.pop()print(f"Printing model:{current_design}")completed_models.append(current_design)def show_completed_models(completed_models):print("The following models have been printed:")for completed_model in completed_models:print(completed_model)unprinted_designs = ['phone case', 'robot pendant', 'dodecahedron']
completed_models = []
print_models(unprinted_designs, completed_models)
show_completed_models(completed_models)#禁止函数修改列表
print_models(unprinted_designs[:], completed_models)

传递任意数量的实参

#传递任意数量的实参数
def make_pizza(*toppings):print(toppings)make_pizza('pepperoni')
make_pizza('mushrooms', 'green peppers', 'extra cheese')#结合使用位置实参和任意数量实参
def make_pizza_size(size, *toppings):print(f"Making a {size} pizza with the following toppings:")for top in toppings:print(f"-{top}")make_pizza_size(16, 'pepperoni')
make_pizza_size(12, 'mushrooms', 'green peppers', 'extra cheese')#使用任意数量的关键字实参数
def build_profile(first, last, **user_info):user_info['first_name'] = firstuser_info['last_name'] = lastreturn user_infouser_info = build_profile('albert', 'einstein', location='princeton', field='physics')
print(user_info)

将函数存储在模块中

1、导入整个模块

pizza.py

def make_pizza(size, *toppings):print(f"Making a {size} pizza with the following toppings:")for top in toppings:print(f"-{top}")

pizza_main.py

import pizzapizza.make_pizza(16, 'pepperoni')
pizza.make_pizza(12, 'mushrooms', 'green peppers', 'extra cheese')

2、导入特定的函数

#导入单个函数
from module_name import function_name#导入多个函数
from module_name import function_0, function_1

from pizza import make_pizzamake_pizza(16, 'pepperoni')
make_pizza(12, 'mushrooms', 'green peppers', 'extra cheese')

3、使用 as 给函数指定别名

from pizza import make_pizza as mpmp(16, 'pepperoni')
mp(12, 'mushrooms', 'green peppers', 'extra cheese')

4、使用 as 给模块指定别名

import pizza as pp.make_pizza(16, 'pepperoni')
p.make_pizza(12, 'mushrooms', 'green peppers', 'extra cheese')

函数编写指南

给形参指定默认值时，等号两边不要有空格：

def function_name(parameter_0, parameter_1='default value')

对于函数调用中的关键实参，也遵循整个约定

function_name(value_0, parameter_1='value')

函数参数缩进对齐

def function_name(parameter_0, parameter_1, parameter_2,parameter_3, parameter_4, parameter_5):

使用空行分隔多个函数

所有import 语句都放在文件开头