1、
def discount(price,rate): ## 定义函数名discount，两个形式参数price和rate sell_price = price * rate return sell_price ## 函数返回售价 price = float(input("please input the price:")) ## 此处接受输入原价 rate = float(input("please input the rate:")) ## 此处接受输入折扣率 final_price = discount(price,rate) ## 调用discount函数，使用位置参数 print("the price after discount is %.2f:" % final_price) ## 输出最终价格
## 以上函数， price、rate、final_price为全局变量， sell_price为局部变量
please input the price:800 please input the rate:0.6 the price after discount is 480.00:
2、
def discount(price,rate): sell_price = price * rate return sell_price price = float(input("please input the price:")) rate = float(input("please input the rate:")) final_price = discount(price,rate) print("the price after discount is %.2f:" % final_price) print("output sell_price:",sell_price) ## 此处尝试调用局部变量
please input the price:800 please input the rate:0.6 the price after discount is 480.00: Traceback (most recent call last): File "D:/programs/python/Lib/idlelib/a.py", line 8, in <module> print("output sell_price:",sell_price) NameError: name 'sell_price' is not defined ## 不能调用局部变量
3、
def discount(price,rate): sell_price = price * rate print("please show the price again:", price) print("please show the rate again:",rate) return sell_price price = float(input("please input the price:")) rate = float(input("please input the rate:")) final_price = discount(price,rate) ## 在调用discount函数时，调用了全局变量price和rate print("the price after discount is %.2f:" % final_price)