python之路——list操作

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)

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