列表list的增删改查

# _author:VULCAN
# date:2018/8/14
a = ["张三", "李四", "王五", "马六", "王五", "李七"]

# 对列表的查询操作(切片)：
# print(a[0])
# print(a[0:])#依次打印到最后等同于 print(a[0::1])
# print(a[1::2])#从左到右每隔一个去取值  2是步长
# print(a[3::-3])#从右到左每搁两个去取值
# print(a[-3::2])#从左到右每搁一个去取值
# print(a[-3::-2])#从右到左每隔一个去取值
# print(a[1:-1:-1])#结果为空值
# print("李四" in a)
# print("李四" not in a)


# 添加操作：append insert
# a.append('周八')#默认添加在做后面,追加
# print(a)
# a.insert(2, '黎明')
# print(a)#添加值时需要索引值

# 修改操作：
# a[0] = "王麻子"#直接根据下标修改值     a[index] = 新的值
# print(a)
# a[1: 3] = ["第三方", "安抚"]#根据索引范围来修改值    a[start:end] = [a,b,c]
# print(a)

# 删除操作：remove pop del
# a.remove(a[2])
# a.remove("李七")#直接删除某一个值
# print(a)

#清空列表
# a.clear()
# print(a)

# a.pop(2)
# print(a)#根据下标删除

# del a[1:3]#连续删除某些值
# del a[0::2]#del可以添加切片
# print(a)

# del()可以删除整个列表
# del a
# print(a)





# count()：计算元素在列表中的个数
# l = [1, 1, 11, 1, 33, 45, 46, 46, 46813, 1345, 54, 64, 64, 46, 43, 891].count(1)
# m = ["999", "999", "999", "666", "666", "888", "777", "555", "333"].count("999")
# print(l)
# print(m)

# extend():把后边的数据添加到前边的数据中，对数据进行扩展
# a = [1, 2, 3, 4]
# b = [7, 8, 9, 10]
# a.extend(b)
# print(a)
# print(b)

# index():根据元素名字查找元素的下标位置
# print(a.index("张三"))

# reverse():对元素进行倒序排列，没有返回值
# a.reverse()
# print(a)

# sort方法,对一组数据进行排序，从小到大
# b = [543, 2657, 5, 2345, 57, 67, 5, 345, 245, 4, 54]
# b.sort()
# print(b)
# b.sort(reverse=True)#reverse=True默认是true,设为false后就是将数据先从小到大排序，再把得到的数据从新从大到小排序
# print(b)
#sorted()效果等同于sort()
# x = sorted(b)
# print(x)

# name0='wuchao'
# name1='jinxin'
# name2='xiaohu'
# name3='sanpang'
# name4='ligang'
#
# names='wuchao jinxing xiaohu sanpang ligang'

# a=['wuchao','jinxin','xiaohu','sanpang','ligang',['wuchao','jinxin']]

# 增删改查
# 查  切片 []
# print(a[1:])#取到最后
# print(a[1:-1])#取到倒数第二值
# print(a[1:-1:1])#从左到右一个一个去取
# print(a[1::2])#从左到右隔一个去取
# print(a[3::-1])
# b=a[3::-1]
# print(b)#['sanpang', 'xiaohu', 'jinxin', 'wuchao']
# print(a[-2::-1])
# print(a[1:-1:-2])

# 添加 append insert

# a.append('xuepeng')  #默认插到最后一个位置
# print(a)
# a.insert(1,'xuepeng') #将数据插入到任意一个位置
# print(a)

# 修改
#
# a[1]='haidilao'
# print(a)
# a[1:3]=['a','b']
# print(a)


# 删除 remove pop del

# a.remove(a[0])
# print(a)
# b=a.pop(1)
# print(a)
# print(b)
#
# del a[0]
# print(a)
# del a
# print(a)
# a.remove(['wuchao','jinxin'])
# print(a)


# count:计算某元素出现次数
# t=['to', 'be', 'or', 'not', 'to', 'be'].count('to')
# print(t)

# extend
# a = [1, 2, 3]
# b = [4, 5, 6]
# a.extend(b)
# print(a)
# print(b)

# index #  根据内容找位置

# a = ['wuchao', 'jinxin', 'xiaohu','ligang', 'sanpang', 'ligang', ['wuchao', 'jinxin']]
#
#
# first_lg_index = a.index("ligang")
# print("first_lg_index",first_lg_index)
# little_list = a[first_lg_index+1:]
#
# second_lg_index = little_list.index("ligang")
# print("second_lg_index",second_lg_index)
#
# second_lg_index_in_big_list = first_lg_index + second_lg_index +1
#
# print("second_lg_index_in_big_list",second_lg_index_in_big_list)
# print("second lg:",a[second_lg_index_in_big_list])

# reverse

# a = ['wuchao', 'jinxin', 'xiaohu','ligang', 'sanpang', 'ligang']
# a.reverse()
# print(a)

# x = [4, 6, 2, 1, 7, 9]
# x.sort(reverse=True)
# print(x)#[1, 2, 4, 6, 7, 9]


a = ['wuchao', 'jinxin', 'Xiaohu', 'Ligang', 'sanpang', 'ligang']
# a.sort()
# print(a)

print(a.count("haidilao ge"))
print(a.pop())
print(a)