python之路——list操作_python list 取出倒数2个元素并且删除-优快云博客

本文链接：https://blog.youkuaiyun.com/weixin_39501270/article/details/75202950

本文详细介绍了Python列表的基本操作，包括添加、删除、更新和查找等核心功能，并通过具体示例展示了如何利用这些操作来管理和处理列表数据。

list操作

1.添加操作

追加append
- 追加成功后会在集合最后位置添加对应的元素

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
names1.append('LL')
print(names1)

print —>:
[‘nick’, ‘judy’, ‘atong’, ‘lulu’, ‘TT’, ‘nick’, ‘judy’, ‘atong’, ‘lulu’, ‘TT’, ‘LL’]

指定位置插入元素
- 在指定位置添加后，该元素占住指定位置，后面的元素依次后移

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
names1.insert(4, 'OOP')

print—>:
[‘nick’, ‘judy’, ‘atong’, ‘lulu’, ‘OOP’, ‘TT’, ‘nick’, ‘judy’, ‘atong’, ‘lulu’, ‘TT’]

扩展列表
- 对于两个列表来说我们可以通过扩展函数将两个解表中的元素进行合并

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]

names1.extend(names2)
print(names1)

print—>:
[‘nick’, ‘judy’, ‘atong’, ‘lulu’, ‘TT’, ‘nick’, ‘judy’, ‘atong’, ‘lulu’, ‘TT’, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0]

2.删除操作

移出操作
无参数的情况

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
names1.pop()
print(names1)

print—>:
[‘nick’, ‘judy’, ‘atong’, ‘lulu’, ‘TT’, ‘nick’, ‘judy’, ‘atong’, ‘lulu’]

有参数的情况

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
names1.pop(len(names1)-2)
print(names1)

print—>:
[‘nick’, ‘judy’, ‘atong’, ‘lulu’, ‘TT’, ‘nick’, ‘judy’, ‘atong’, ‘TT’]

清空操作

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
names2.clear()
print(names2)

print—>:
[]

remove操作
remove操作输入的参数集合中必须存在，如果不存在则会报错，可以使用if ‘element’ in list 进行判断

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
names1.remove('TT')
print(names1)

print—>:
[‘nick’, ‘judy’, ‘atong’, ‘lulu’, ‘nick’, ‘judy’, ‘atong’, ‘lulu’, ‘TT’]

3.更新操作

update

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
names1[0] = 'cloud'
print(names1)

print—>:
[‘cloud’, ‘judy’, ‘atong’, ‘lulu’, ‘TT’, ‘nick’, ‘judy’, ‘atong’, ‘lulu’, ‘TT’]

4.查找操作

切片
切面操作是顾首不顾尾
选取a至b范围的元素

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
print(names1[0:2])

print—>:
[‘nick’, ‘judy’]

从首位开始选取可以使用简单的方式书写

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
print(names1[:2])

print—>:
[‘nick’, ‘judy’]

选取到最后一位

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
print(names1[:])

print—>:
[‘nick’, ‘judy’, ‘atong’, ‘lulu’, ‘TT’, ‘nick’, ‘judy’, ‘atong’, ‘lulu’, ‘TT’]

以步进的形式进行切片选取

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
print(names1[::2])

print—>:
[‘nick’, ‘atong’, ‘TT’, ‘judy’, ‘lulu’]

选取最后一位和倒数第二位元素

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
print(names1[-1])
print(names1[-2])

print—>:
TT
lulu

对集合中的元素进行计数

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
print(len(names1))
print(names1.count('atong'))
print(names1.count('GG'))

print—>:
10
2
0

对集合中的元素进行反转

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
names1.reverse()
print(names1)

print—>:
[‘TT’, ‘lulu’, ‘atong’, ‘judy’, ‘nick’, ‘TT’, ‘lulu’, ‘atong’, ‘judy’, ‘nick’]

对集合中的元素进行排序
默认按照ascii码大小进行排序

names1 = ['nick', 'judy', 'atong', 'lulu', 'TT', 'nick', 'judy', 'atong', 'lulu', 'TT']
names2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
names1.sort()
print(names1)