27、

<pre>
print(not False)
print(not True)
print(True or False)
print(True or True)
print(False or True)
print(False or False)
print(True and False)
print(True and True)
print(False and True)
print(False and False)
print(not (True or False))
print(not (True or True))
print(not (False or True))
print(not (False or False))
print(not (True and False))
print(not (True and True))
print(not (False and True))
print(1 != 0)
print(1 != 1)
print(0 != 1)
print(0 != 0)
print(1 == 0)
print(1 == 1)
print(0 == 1)
print(0 == 0)
输出：
True
False
True
True
True
False
False
True
False
False
False
False
False
True
True
False
True
True
False
True
False
False
True
False
True
</pre>

28、

<pre>
print(True and True)
print(False and True)
print(1 == 1 and 2 == 1)
print("test" == "test")
print(1 == 1 or 2 != 1)
print(True and 1 == 1)
print(False and 0 != 0)
print(True or 1 == 1)
print("test" == "testing")
print(1 != 0 and 2 == 1)
print("test" != "testing")
print("test" == 1)
print(not (True and False))
print(not (1 == 1 and 0 != 1))
print(not (10 == 1 or 1000 == 1000))
print(not (1 != 10 or 3 == 4))
print(not ("testing" == "testing" and "Zed" == "Cool Guy"))
print(1 == 1 and not ("testing" == 1 or 1 == 0))
print("chunky" == "bacon" and not (3 == 4 or 3 == 3))
print(3 == 3 and not ("testing" == "testing" or "Python" == "Fun"))
输出：
True
False
False
True
True
True
False
True
False
False
True
False
True
False
False
False
True
True
False
False
</pre>

<pre>
思考题：

运算符 >,<,<=,>=

</pre>

29、

<pre>
people = 20
cats = 30
dogs = 15
if people < cats: #如果people小于cats
print("too many cats! the world is doomed!")
if people > cats: #如果people大于cats
print("not many cats! the world is saved!")
if people < dogs: #如果people小于dogs
print("the world is drooled on!")
if people > dogs: #如果people大于dogs
print("the world is dry!")
dogs += 5 #dogs每轮增加5
if people >= dogs: #peoples大于等于dogs
print("people are greater than or equal to dogs.")
if people <= dogs: #peoples小于等于dogs
print("people are less than or equal to dogs.")
if people == dogs: #peoples等于dogs
print("people are dogs.")

这里因为没写明dogs小于peoples会发生什么。所以在后面就会停止。

输出：
too many cats! the world is doomed!
the world is dry!
people are greater than or equal to dogs.
people are less than or equal to dogs.
people are dogs.
</pre>

<pre>
思考题：

不缩进，程序之间的运行逻辑就会乱。只要是true的结果都会运行。改掉后。如果if的判断不是true，就不会有返回了。

</pre>

30、

<pre>
people = 30
cars = 40
buses = 15
if cars > people: #cars的值大于people
print("We should take the cars.")
elif cars < people:#cars的值小于people
print("We should not take the cars.")
else: #其他情况
print("We can't decide.")
if buses > cars:#buses大于cars
print("That's too many buses.")
elif buses < cars: #buses小于cars
print("Maybe we could take the buses.")
else: #其他情况
print("We still can't decide.")
if people > buses: #people的值大于buses
print("Alright, let's just take the buses.")
else: #其他情况
print("Fine, let's stay home then.")
输出：
We should take the cars.
Maybe we could take the buses.
Alright, let's just take the buses.

</pre>

<pre>
思考题：
注释见上面
else是只所有的其他情况，elif是要有具体的情况判断语句的。
</pre>

31、

<pre>

31

print("you enter a dark room with two doors. do you go through door #1 or door #2?")
door = input("> ")
if door == "1":
print("there's a giant bear here eating a cheese cake. what do you do?")
print("1.take the cake.")
print("2.scream at the bear.")
bear = input("> ")
if bear == "1":
print("the bear eats your face off. good job!")
elif bear == "2":
print("the bear eats your legs off. good job!")
else:
print("well,doing %s is probably better. bear runsaway." % bear)
elif door == "2":
print("you stare into the endless abyss at cthulhu's retina.")
print("1.blueberries.")
print("2.yellow jacket clothespins.")
print("3.understanding revolvers yelling melodies.")
insanity = input("> ")
if insanity == "1" or insanity == "2":
print("your body survives powered by a mind of jello.good job!")
else:
print("the insanity rots your eyes into a pool of muck.good job")
else:
print("you stumble around and fall on a knife and die.good job")
输出：
you enter a dark room with two doors. do you go through door #1 or door #2?

1
there's a giant bear here eating a cheese cake. what do you do?
1.take the cake.
2.scream at the bear.
2
the bear eats your legs off. good job!

</pre>

<pre>
思考题：
这游戏设计头疼。
</pre>

32、

<pre>
the_count = [1,2,3,4,5]
fruits = ["apples","oranges","pears","apricots"]
change = [1,"pennies",2,"dimes",3,"quarters"]

this first kind of for-loop goes through a list

for number in the_count:
print("this is count %d" % number)

same as above

for fruit in fruits:
print("a fruit of type: %s" % fruit)

also we can go through mixed lists too

notice we have to use %r since we don't know what's in it

for i in change:
print("i got %r" % i)

we can also build lists, first start with an empty one

element = []

then use the range function tu do 0 to 5 counts

for i in range(0,6):
print("adding %d to the list." % i)
#append is a function that lists understand
element.append(i)

now we can print them out too

for i in element:
print("element was:%d" % i )
输出：
this is count 1
this is count 2
this is count 3
this is count 4
this is count 5
a fruit of type: apples
a fruit of type: oranges
a fruit of type: pears
a fruit of type: apricots
i got 1
i got 'pennies'
i got 2
i got 'dimes'
i got 3
i got 'quarters'
adding 0 to the list.
adding 1 to the list.
adding 2 to the list.
adding 3 to the list.
adding 4 to the list.
adding 5 to the list.
element was:0
element was:1
element was:2
element was:3
element was:4
element was:5
</pre>

<pre>
思考题：
在第 22 行，你可不可以直接将 elements 赋值为 range(0,6)，而无需使用 for 循环？ 不可以。。
在 Python 文档中找到关于列表的内容，仔细阅读以下，除了 append 以外列表还支持哪些操作？
http://www.jb51.net/article/47978.htm
</pre>

33、

<pre>
i = 0
number = []
while i < 6:
print("at the top i is %d" % i )
number.append(i)
i = i + 1
print("numbers now:" , number)
print("at the bottom i is %d" % i)
print("the numbers:")
for num in number:
print(num)

输出：
at the top i is 0
numbers now: [0]
at the bottom i is 1
at the top i is 1
numbers now: [0, 1]
at the bottom i is 2
at the top i is 2
numbers now: [0, 1, 2]
at the bottom i is 3
at the top i is 3
numbers now: [0, 1, 2, 3]
at the bottom i is 4
at the top i is 4
numbers now: [0, 1, 2, 3, 4]
at the bottom i is 5
at the top i is 5
numbers now: [0, 1, 2, 3, 4, 5]
at the bottom i is 6
the numbers:
0
1
2
3
4
5
</pre>

<pre>
思考题：

函数暂时不会。

接下来使用 for-loop 和 range 把这个脚本再写一遍。你还需要中间的加值操作吗？如果你不去掉它，会有什么样的结果？

</pre>

34、

<pre>
animals = ["bear","tiger","penguin","zebra"]
bear = animals[1]
print(bear)

记住: ordinal == 有序，以 1 开始；cardinal == 随机选取, 以 0 开始。

输出：tiger
</pre>

<pre>
思考题：
无
</pre>