# 练习24. 更多的练习 你离这本书第一部分的结尾已经不远了，你应该已经具备了足够的 Python 基础知识，可以继续学习一些编程的原理了，但你应该做更多的练习。这个练习的内容比较长，它的目的是锻炼你的毅力，下一个习题也差不多是这样的，好好完成它们，做到完全正确，记得仔细检查。 ~~~ print "Let's practice everything." print 'You\'d need to know \'bout escapes with \\ that do \n newlines and \t tabs.' poem = """ \tThe lovely world with logic so firmly planted cannot discern \n the needs of love nor comprehend passion from intuition and requires an explanation \n\t\twhere there is none. """ print "--------------" print poem print "--------------" five = 10 - 2 + 3 - 6 print "This should be five: %s" % five def secret_formula(started): jelly_beans = started * 500 jars = jelly_beans / 1000 crates = jars / 100 return jelly_beans, jars, crates start_point = 10000 beans, jars, crates = secret_formula(start_point) print "With a starting point of: %d" % start_point print "We'd have %d beans, %d jars, and %d crates." % (beans, jars, crates) start_point = start_point / 10 print "We can also do that this way:" print "We'd have %d beans, %d jars, and %d crates." % secret_formula(start_point) ~~~ ## 你看到的结果 ~~~ $ python ex24.py Let's practice everything. You'd need to know 'bout escapes with \ that do newlines and tabs. -------------- The lovely world with logic so firmly planted cannot discern the needs of love nor comprehend passion from intuition and requires an explanation where there is none. -------------- This should be five: 5 With a starting point of: 10000 We'd have 5000000 beans, 5000 jars, and 50 crates. We can also do that this way: We'd have 500000 beans, 500 jars, and 5 crates. ~~~ ## 附加题 > 1. 记得仔细检查结果，从后往前倒着检查，把代码朗读出来，在不清楚的位置加上注释。 > 1. 故意把代码改错，运行并检查会发生什么样的错误，并且确认你有能力改正这些错误。 ## 常见问题 ### Q:为什么在后面你把 `jelly_beans` 这个变量叫做 `beans`? > 这是函数如何工作的一部分。记住，在函数中，变量都是临时的.当你返回一个变量的时候，你可以把它赋值给另一个变量。我只是定义了一个叫做‘beans’的新变量去接收返回值。 ### Q:你所说的反向阅读代码是什么意思? > 从最后一行开始阅读。对比你的代码和我的是不是一样。如果确认一样，向上移动一行阅读，直到你读到脚本的第一行为止。 ### Q:那首诗是谁写的？ > 我写的。