笨办法19函数和变量

以下为代码：

def cheese_and_crackers(cheese_count, boxes_of_crackers): #定义函数
    print "You have %d cheeses!" % cheese_count
    print "You have %d boxes of crackers!" % boxes_of_crackers
    print "Man that's enough for a party!"
    print "Get a blanket.\n"


print "We can just give the function numbers directly:"
cheese_and_crackers(20, 30)

print "OR, we can use variables from our script:" #通过变量执行
amount_of_cheese = 10
amount_of_crackers = 50
cheese_and_crackers(amount_of_cheese, amount_of_crackers)

print "We can even do math inside too:" #通过math执行
cheese_and_crackers(10 + 20, 5 + 6)

print "And we can combine the two, variables and math:" #通过变量+math执行
cheese_and_crackers(amount_of_cheese + 100, amount_of_crackers + 1000)

输出结果：

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获取用户输入：

def cheese_and_crackers(cheese_count, boxes_of_crackers):
    print "You have %d cheeses!" % cheese_count
    print "You have %d boxes of crackers!\n" % boxes_of_crackers

num1 = raw_input("cheeses:")
num2 = raw_input("crackers:")

cheese_and_crackers(num1, num2)

然而执行到用户输入后，报错 

查看问题发现，报错由于变量的类型不正确，即%d和raw_input的问题，原因是raw_input() 将所有输入作为字符串看待，返回的是字符串类型。可以有以下解决办法： 
1. 将%d换成%r或者%s 
2. 将raw_input换成input，input() 返回所输入的数字的类型（ int, float ） 
3. 第8行加入int: cheese_and_crackers(int(num1), int(num2))

以下用方法2

def cheese_and_crackers(cheese_count, boxes_of_crackers):
    print "You have %d cheeses!" % cheese_count
    print "You have %d boxes of crackers!\n" % boxes_of_crackers

num = "Please enter the number"
num1 = input(num + ", cheeses:")
num2 = input(num + ", crackers:")

cheese_and_crackers(num1, num2)

顺利输出结果： 

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