2-05列表练习题

1.创建一个空列表，命名为names，往里面添加old_driver, rain, jack, shanshan,peiqi,black_girl 元素

names=[]
names.append('old_driver')
names.append('rain')
names.append('jack')
names.append('shanshan')
names.append('peiqi')
names.append('black_girl')
print(names)

2.往names列表里black_gril前面插入一个alex

names.insert(5,'alex')
print(names)

3.把shanshan的名字改成中文姗姗

names[3]='姗姗'

4.往names列表里rain的后面插入一个子列表，[oldboy, oldgirl]

names.insert(2,['oldboy','oldgirl'])

5.返回peiqi的索引值

i = names.index('peiqi')

6.创建新列表[1,2,3,4,2,5,6,2]合并入names列表

L1 = [1,2,3,4,2,5,6,2]
names.extend(L1)

7.取出names列表中索引4-7的元素

print(names[4:8])

8.取出names列表中索引2-10的元素，步长为2

print(names[2:11:2])

9.取出names列表中最后3个元素

print(names[-3::])

10.循环names列表，打印每个元素的索引值，和元素

count = 0
for i in names:
    print(count,i)
    count+=1

# 方法2 enumerate 枚举
for index, i in enumerate(names):
    print(index,i)

11.循环names列表，打印每个元素的索引值和元素，当索引值为偶数时，把对应的元素改为-1

#方法1
# count = 0
# for i in names:
#     print(count,i)
#     if count%2 == 0:
#         names[count] = -1
#     count+=1
# print(names)

# 方法2 enumerate 枚举
for index, i in enumerate(names):
    print(index,i)
    if index % 2 == 0 :
        names[index] = -1
print(names)

12.names里有3个2，请返回地2个2的索引值，不要人肉数，要动态找（提示，找到第一个2的位置，再次基础上再找第2个）

first_index = names.index(2)
names_new = names[first_index+1:]
sec_index = first_index + names_new.index(2)+1
print(sec_index)

 13.现有商品列表如下：

products = [['Iphone8',6888],['MacPro',14800],['小米6',2499],['Coffee',31],['Book',80],['Nike Shoes',799]]

需要打印出这样的格式：

----------------商品列表------------------

0.Iphone8 6888

1.MacPro 14800

2.小米6  2499

3.Coffee   31

4.Book  80

5.Nike Shoes  Nike Shoes

products = [['Iphone8',6888],['MacPro',14800],['小米6',2499],['Coffee',31],['Book',80],['Nike Shoes',799]]

print("-----------商品列表-------------")
for index, i in enumerate(products):
        print("%s.  %s   %d"%(index,i[0],i[1]))

　14.写一个循环，不断的问用户买什么，用户选择一个商品编号，就把对应的商品添加到购物车里，最终用户输入q时退出，打印购物车里的商品列表。

products = [['Iphone8',6888],['MacPro',14800],['小米6',2499],['Coffee',31],['Book',80],['Nike Shoes',799]]
shopping_cart = []
while True:
    user_choice = input("输入要买的商品编号：")
    if user_choice == 'q':
        break
    elif user_choice.isdigit():
        user_choice = int(user_choice)
        if user_choice >= 0 and user_choice <len (products):
            shopping_cart.append(products[user_choice])
        else:
            print("商品不存在")
    else:
        print("选择无效")

if len(shopping_cart) > 0 :
    print("-----------购物车中的商品列表-------------")
    for index, i in enumerate(shopping_cart):
         print("%s.  %s   %d"%(index,i[0],i[1]))