【Python爬虫】-笨办法学 Python 习题27-34

习题28

表达式	值True
True and True	True
False and True	False
1 == 1 and 2 == 1	False
"test" == "test"	True
1 == 1 or 2 != 1	True
True and 1 == 1	True
False and 0 != 0	False
True or 1 == 1	True
"test" == "testing"	False
1 != 0 and 2 == 1	False
"test" != "testing"	True
"test" == 1	False
not (True and False)	True
not (1 == 1 and 0 != 1)	False
not (10 == 1 or 1000 == 1000)	False
not (1 != 10 or 3 == 4)	False
not ("testing" == "testing" and "Zed" == "Cool Guy")	True
1 == 1 and not ("testing" == 1 or 1 == 0	True
"chunky" == "bacon" and not (3 == 4 or 3 == 3)	False
3 == 3 and not ("testing" == "testing" or "Python" == "Fun")	False

加分题：

header 1	header 2
！=	不等于
！	非
==	等于
>=	大于等于
<=	小于等于
and	且
or	或
&	且

习题29:

# -*- coding:utf-8 -*-
people=20
cats=30
dogs=15

if peoplecats:
    print("Not many cats!The world is saved")
if peopledogs:
    print("The world is dry")
    

dogs +=5

if people>=dogs:
    print("People are greater than or equall to dogs");

if people<=dogs:
    print("People are less than or equal to dogs")

if people

习题30：

people = 30
cars = 40
buses = 15
if cars > people:
    print("We should take the cars.")
elif cars < people:
    print("We should not take the cars.")
else:
    print("We can't decide.")
if buses > cars:
    print("That's too many buses.")
elif buses < cars:
    print("Maybe we could take the buses.")
else:
    print("We still can't decide.")
if people > buses:
    print("Alright, let's just take the buses.")
else:
    print("Fine, let's stay home then.")

习题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 runs away." % 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!")

习题32

the_count = [1, 2, 3, 4, 5]
fruits = ['apples', 'oranges', 'pears', 'apricots']
change = [1, 'pennies', 2, 'dimes', 3, 'quarters']

for number in the_count:
    print("This is count {}".format(number))
# same as above
for fruit in fruits:
    print("A fruit of type: {}".format(fruit))
for i in change:
    print("I got {}".format(i))

elements = []

for i in range(0, 6):
    print("Adding {} to the list.".format(i))
# append is a function that lists understand
elements.append(i)
# now we can print them out too
for i in elements:
    print("Element was: {}".format(i))

加分习题

//1. range(x,y) 产生一个包含x，不包含y的序列。
//2. 直接将elements赋值为range(0,6),elements是range(0,6),而不是数值
//3. # 列表方法
List=[1,2,3,1]
List.append(4) #向列表末尾添加新的对象
print(List.count(1)) #用于统计某个元素在列表中出现的次数
List.extend([5,6,7])    #用于向一个列表之后添加另一个序列。
print(List.index(2))    #从列表中查找出某个值第一个匹配项的位置
List.insert(3,'insert') #向列表指定位置添加一个元素
List.pop()#移除列表的一个元素，并且返回该元素的值。如果给了参数，则删除该位置的元素
print(List)
List.reverse()  #将列表元素反向存放
print(List)

List.remove(1) #移除列表中某个值得第一个匹配项
print(List)
List=[6,5,7,9,4]
List.sort() #将列表元素进行排序
print(type(List.sort()))    #验证List.sort()返回值为None
print(List)

习题33

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

加分题

1.
i = 0
x = 6
numbers = []
while(i < x):
    print("At the top i is %d" % i)
    numbers.append(i)
    i = i + 1
    print("Numbers now: ", numbers)
    print("At the bottom i is %d" % i)
print("The numbers: ")
for num in numbers:
    print(num)
    
    
3.
i = 0
x = 6
val = int(input("input num:"))
numbers = []
while(i < x):
    print("At the top i is %d" % i)
    numbers.append(i)
    i = i + val
    print("Numbers now: ", numbers)
    print("At the bottom i is %d" % i)
print("The numbers: ")
for num in numbers:
    print(num)
    
    
5.numbers = []
for i in range(0,6):
    print("At the top i is %d" % i)
    numbers.append(i)
    print("Numbers now: ", numbers)
    print("At the bottom i is %d" % i)

print("The numbers: ")
for num in numbers:
    print(num)