笨办法学python习题19 函数和变量

这次的习题主要探讨的是函数的参数部分可有有哪些组成方式。另外强调的是：函数里的变量和脚本里的变量之间是没有联系的。

代码如下：

#-*-coding:utf-8-*-def cheese_and_crackers(cheese_count,boxes_of_crackers):print"You have %d cheeses!" %cheese_countprint"You have %d boxes of crackers!"%boxes_of_crackersprint"Man that's enough for a party!"print"Get a blanket.\n"#函数参数为数字print"We can just give the function numbers directly:"cheese_and_crackers(20,30)#函数参数为变量print"OR, we can use variables from our script:"amount_of_cheese = 10amount_of_crackers = 50cheese_and_crackers(amount_of_cheese,amount_of_crackers)#函数参数为数学表达式print"We can even do math inside too:"cheese_and_crackers(10+20,5+6)#函数参数为变量、数字、数学表达式print"And we can combine the two,variables and math:"cheese_and_crackers(amount_of_cheese+100, amount_of_crackers+1000)

运行结果如下：

simengred$ python ex19.pyWe can just give the function numbers directly:You have 20 cheeses!You have 30 boxes of crackers!Man that's enough for a party!Get a blanket.OR, we can use variables from our script:You have 10 cheeses!You have 50 boxes of crackers!Man that's enough for a party!Get a blanket.We can even do math inside too:You have 30 cheeses!You have 11 boxes of crackers!Man that's enough for a party!Get a blanket.And we can combine the two,variables and math:You have 110 cheeses!You have 1050 boxes of crackers!Man that's enough for a party!Get a blanket.

1,从代码和运行结果来看，函数中的变量可以是数字、变量、数学表达式甚至是变量和数学表达式和变量组合使用。

2,如果函数参数中的变量和脚本里面的变量命名完全相同，程序运行也是没有问题的。但是应当尽量避免，以免引起不必要的混淆。

例如：

#-*-coding:utf-8-*-def cheese_and_crackers(cheese_count,boxes_of_crackers):print"You have %d cheeses!" %cheese_countprint"You have %d boxes of crackers!"%boxes_of_crackersprint"Man that's enough for a party!"print"Get a blanket.\n"#函数参数为数字print"We can just give the function numbers directly:"cheese_and_crackers(20,30)#函数参数为变量print"OR, we can use variables from our script:"cheese_count = 10amount_of_crackers = 50cheese_and_crackers(cheese_count,amount_of_crackers)#函数参数为数学表达式print"We can even do math inside too:"cheese_and_crackers(10+20,5+6)#函数参数为变量、数字、数学表达式print"And we can combine the two,variables and math:"cheese_and_crackers(cheese_count+100, amount_of_crackers+1000)