# 練習24. 更多的練習 你離這本書第一部分的結尾已經不遠了，你應該已經具備了足夠的 Python 基礎知識，可以繼續學習一些編程的原理了，但你應該做更多的練習。這個練習的內容比較長，它的目的是鍛煉你的毅力，下一個習題也差不多是這樣的，好好完成它們，做到完全正確，記得仔細檢查。 ~~~ 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) ~~~ ## 你看到的結果 ~~~ $ 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. ~~~ ## 附加題 > 1. 記得仔細檢查結果，從后往前倒著檢查，把代碼朗讀出來，在不清楚的位置加上注釋。 > 1. 故意把代碼改錯，運行并檢查會發生什么樣的錯誤，并且確認你有能力改正這些錯誤。 ## 常見問題 ### Q:為什么在后面你把 `jelly_beans` 這個變量叫做 `beans`? > 這是函數如何工作的一部分。記住，在函數中，變量都是臨時的.當你返回一個變量的時候，你可以把它賦值給另一個變量。我只是定義了一個叫做‘beans’的新變量去接收返回值。 ### Q:你所說的反向閱讀代碼是什么意思? > 從最后一行開始閱讀。對比你的代碼和我的是不是一樣。如果確認一樣，向上移動一行閱讀，直到你讀到腳本的第一行為止。 ### Q:那首詩是誰寫的？ > 我寫的。