Python学习-函数基本操作

def function():  #定义一个函数
    a = 1
    b = 2
    c = a + b
    print ("a =", a)
    print ("b =", b)
    print ("c =", c)
    print ("a+b=", c)
function()
'''
结果为：
a = 1
b = 2
c = 3
a+b= 3
'''


def function2(a,b):  #定义带有参数的函数，参数a、b只在函数内部发生作用
    c = a+b
    print("a =", a)
    print("b =", b)
    print("c =", c)
    print("a+b=", c)
function2(10,20)
'''
结果为:
a = 10
b = 20
c = 30
a+b= 30
'''


def function3(a=10,b=20):  #设置函数的默认值
    c = a + b
    print("a =", a)
    print("b =", b)
    print("c =", c)
    print("a+b=", c)
function3()
'''
结果为：
a = 10
b = 20
c = 30
a+b= 30
'''
function3(50)
'''
结果为：
a = 50
b = 20
c = 70
a+b= 70
'''
function3(30,40)
'''
结果为：
a = 30
b = 40
c = 70
a+b= 70
'''

def function4(a,b=20):  # 函数的一个参数没有赋值，另一个赋值
    c = a + b
    print("a =", a)
    print("b =", b)
    print("c =", c)
    print("a+b=", c)
function3(50)  #为没有赋值的参数赋值
'''
结果为：
a = 50
b = 20
c = 70
a+b= 70
'''


a = 1000
def function5(b=20):
    global a  #使用全局变量
    c = a + b
    print("a =", a)
    print("b =", b)
    print("c =", c)
    print("a+b=", c)
function5()
'''
结果为：
a = 1000
b = 20
c = 1020
a+b= 1020
'''


def add(a,b):
    c = a+b
    return c
d= add(1,2)
print(d)
# 结果为： 3