Python入门（04） -- 函数

喜欢ヅ旅行 2022-06-04 06:22 198阅读 0赞

### 一、定义函数 ###

使用函数打印hello world

def say_hello():
        print('Hello world!')
    say_hello()

打印结果：

Hello world!

**1.向函数传递信息**

def say_hello(person_name):
        print("Nice to meet you, " + person_name + "!")
    say_hello("Jhon")

Nice to meet you, Jhon!

### 二、传递实参 ###

**1.位置实参**

def say_hello(first_name, last_name):
        print("Hello, " + first_name.title() + " " + last_name.title())
    say_hello('zhang', 'san')

打印结果：

Hello, Zhang San

**2.关键字实参**

def say_hello(first_name, last_name):
        print("Hello, " + first_name.title() + " " + last_name.title())
    say_hello(first_name = 'zhang', last_name = 'san')

打印结果：

Hello, Zhang San

**3.默认值**

def say_hello(first_name, last_name, middle_name = ''):
        print("Hello, " + first_name.title() + " " 
              + last_name.title()) + middle_name
    say_hello('zhang', 'san')

打印结果：

Hello, Zhang San

### 三、返回值 ###

**1.返回简单值**

def say_hello(first_name, last_name):
        return "Hello, " + first_name.title() + " " + last_name.title()
    print(say_hello('zhang', 'san'))

打印结果：

Hello, Zhang San

**2.返回字典**

def build_person(first_name, last_name):
        person = {
       'first_name': first_name, 'last_name': last_name}
        return person
    build_person('zhang', 'san')
    print(build_person('zhang', 'san'))

打印结果：

{
       'first_name': 'zhang', 'last_name': 'san'}

### 四、传递列表 ###

def say_hello(names):
        for name in names:
            msg = "Hello, " + name.title() + "!"
            print(msg)
    people = ['jhon', 'lili', 'james']
    say_hello(people)

打印结果：

Hello, Jhon!
    Hello, Lili!
    Hello, James!

### 五、传递任意数量的实参 ###

def say_hello(*names):
        print(names)
    say_hello('zhao', 'qian', 'sun')

打印结果：

('zhao', 'qian', 'sun')

1.结合使用位置实参和任意数量实参

def say_hello(age, *names):
        print("Age :" + str(age))
        for name in names:
            print("- Name: " + name)
    say_hello(12, 'zhao', 'qian', 'sun')

打印结果：

Age :12
    - Name: zhao - Name: qian - Name: sun