习题 19: 函数和变量

发布时间：2023-12-21 09:40:14 所属栏目：Asp 来源：DaWei

导读： 函数这个概念也许承载了太多的信息量，不过别担心。只要坚持做这些练习，对照上个练习中的检查点检查一遍这次的联系，你最终会明白这些内容的。有一个你可能没有注意到的细节，我们现在强调

函数这个概念也许承载了太多的信息量，不过别担心。只要坚持做这些练习，对照上个练习中的检查点检查一遍这次的联系，你最终会明白这些内容的。

有一个你可能没有注意到的细节，我们现在强调一下：函数里边的变量和脚本里边的变量之间是没有连接的。下面的这个练习可以让你对这一点有更多的思考：

def cheese_and_crackers(cheese_count, boxes_of_crackers): 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:" 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:" cheese_and_crackers(10 + 20, 5 + 6) print "And we can combine the two, variables and math:" cheese_and_crackers(amount_of_cheese + 100, amount_of_crackers + 1000)

通过这个练习，你看到我们给我们的函数 cheese_and_crackers 很多的参数，然后在函数里把它们打印出来。我们可以在函数里用变量名，我们可以在函数里做运算ASP 变量，我们甚至可以将变量和运算结合起来。

从一方面来说，函数的参数和我们的生成变量时用的 = 赋值符类似。事实上，如果一个物件你可以用 = 将其命名，你通常也可以将其作为参数传递给一个函数。

你应该看到的结果

你应该研究一下脚本的输出，和你想象的结果对比一下看有什么不同。

$ python ex19.py We 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. $

【Python3的代码：

def cheese_and_crackers (cheese_count, boxes_of_crackers): 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:") amount_of_cheese = 10 amount_of_crakers = 50 cheese_and_crackers (amount_of_cheese, amount_of_crakers) print ("We can even do math inside too:") cheese_and_crackers (10 + 20, 5 + 6) print ("And we can combine the two, variables and math:") cheese_and_crackers (amount_of_cheese + 100, amount_of_crakers + 1000)

输出结果为：

We 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.

】

加分习题

1. 倒着将脚本读完，在每一行上面添加一行注解，说明这行的作用。

2. 从最后一行开始，倒着阅读每一行，读出所有的重要字符来。

3. 自己编至少一个函数出来，然后用10种方法运行这个函数。

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