python学习笔记----列表

一、添加：(position 索引.. date数据)
append(data)
把添加的值直接当做一个元素插入列表当中(末尾).

In [9]: list = ['a','b','c','d',]
In [10]: list
Out[10]: ['a', 'b', 'c', 'd']
In [11]: list.append('e')
In [12]: list
Out[12]: ['a', 'b', 'c', 'd', 'e']
#**********************
In [34]: list
Out[34]: ['a', 'b', 'c', 'd', 'e']
In [35]: list1
Out[35]: ['a', 'b']
In [36]: list.append(list1)
In [37]: list
Out[37]: ['a', 'b', 'c', 'd', 'e', ['a', 'b']]
extend(data)

会把添加的值拆开成元素，分别插入到列表当中

In [26]: list
Out[26]: ['a', 'b', 'c', 'd', 'e']
In [27]: list1
Out[27]: ['a', 'b']
In [28]: list.extend(list1)
In [29]: list
Out[29]: ['a', 'b', 'c', 'd', 'e', 'a', 'b']

insert(position,data)

Out[39]: ['a', 'b', 'c', 'd', 'e']
In [40]: list.insert(0,'laowang')
In [41]: list
Out[41]: ['laowang', 'a', 'b', 'c', 'd', 'e']

二、删除：

del list[position].

Out[41]: ['laowang', 'a', 'b', 'c', 'd', 'e']
In [46]: del list[0]
In [47]: list
Out[47]: ['a', 'b', 'c', 'd', 'e']

list.pop() 默认删除末尾

Out[47]: ['a', 'b', 'c', 'd', 'e']
In [48]: list
Out[48]: ['a', 'b', 'c', 'd', 'e']
In [49]: list.pop()
Out[49]: 'e'
In [50]: list
out[50]: ['a', 'b', 'c', 'd']

list.pop(position) 删除指定索引的值

Out[52]: ['a', 'b', 'c', 'd']
In [53]: list.pop(1)
Out[53]: 'b'
In [54]: list
Out[54]: ['a', 'c', 'd']

list.remove(data) 删除指定的值

Out[54]: ['a', 'c', 'd']
In [58]: list.remove('a')
In [59]: list
Out[59]: ['c', 'd']

三、查：
x = list[position]

Out[62]: ['b', 'd']
In [63]: list
Out[63]: ['b', 'd']
In [64]: a = list[1]
In [65]: a
Out[65]: 'd'

四、改：
list[position] = xxx

Out[60]: ['c', 'd']
In [61]: list[0] = 'b'
In [62]: list
Out[62]: ['b', 'd']

升序

list.sort()

In [85]: list
Out[85]: ['1', '3', '4', '5', '7', '9', '2', '4', '6', '8']
In [86]: list.sort()
In [87]: list
Out[87]: ['1', '2', '3', '4', '4', '5', '6', '7', '8', '9']

list.sort(reverse = False)

Out[91]: ['1', '3', '4', '5', '7', '9', '2', '4', '6', '8']
In [92]: list.sort(reverse = False)
In [93]: list
Out[93]: ['1', '2', '3', '4', '4', '5', '6', '7', '8', '9']

降序

list.sort(reverse = True)

Out[93]: ['1', '2', '3', '4', '4', '5', '6', '7', '8', '9']
In [94]: list.sort(reverse = True)
In [95]: list
Out[95]: ['9', '8', '7', '6', '5', '4', '4', '3', '2', '1']

倒序

list[::-1]

Out[95]: ['9', '8', '7', '6', '5', '4', '4', '3', '2', '1']
In [96]: list[::-1]
Out[96]: ['1', '2', '3', '4', '4', '5', '6', '7', '8', '9']

list.reverse()

Out[98]: ['1', '2', '3', '4', '4', '5', '6', '7', '8', '9']
In [99]: list.reverse()
In [100]: list
Out[100]: ['9', '8', '7', '6', '5', '4', '4', '3', '2', '1']

取长度

len(list)

Out[100]: ['9', '8', '7', '6', '5', '4', '4', '3', '2', '1']
In [101]: len(list)
Out[101]: 10

统计元素个数

list.count()

Out[107]: ['9', '8', '7', '6', '5', '4', '4', '3', '2', '1']
In [108]: list.count('4')
Out[108]: 2