3. 函数

1. 定义函数

def function_name(paramaters):

statement1

statement2

statement3

def hello():

print("Hello")

def hello(name):

print("Hello!" + name)

2. Python的函数不能重载

3. 定义有返回值的函数

def function_name(paramaters):

statement1

statement2

statement3

return values

(1) 单值返回

def add(a, b):

return a + b

add(3, 4)

(2) 多值返回

def test(a, b):

c = a + b

d = a - b

e = a * b

return c, d, e

a, b, c = test(3, 4)

re = test(3, 4)

re[0] re[1] re[2]

(3) 参数预设值

预定义值必须靠在右边

def test(a, b = 2):

c = a + b

return c

test(1)

test(1, 5)