习题 24: 更多练习
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)
What You Should See
$ 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.
Study Drills
- 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。
- 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。
Common Student Questions
Why do you you call the variable jelly_beans but the name beans later? |
|---|
That's part of how a function works. Remember that inside the function the variable is temporary. When you return it then it can be assigned to a variable for later. I'm just making a new variable named beans to hold the return value. |
| What do you mean by reading the code backward? |
| Start at the last line. Compare that line in your file to the same line in mine. Once it's exactly the same, move up to the next line. Do this until you get to the first line of the file. |
| Who wrote that poem? |
| I did. Not all of my poems suck. |
Copyright (C) 2010 by
Author: Zed Shaw
Translator：Zander Wong