列表的魔法

以中括号括起来，以","分隔每个元素，列表中的元素可以是数字，字符串，列表中可以嵌套列表。列表的列表中还能嵌套列表，也可以是布尔值。所有的都能放进去。

li = [1,12,9,"age",["hehe",2,"wang",["wanggang","xudong"]],"end"]
print(li[4][3][1])
---
xudong
---

切片

li = [1,12,9,"age",["hehe",2,"wang",["wanggang","xudong"]],"end"]
print(li[3:-1])
---
['age', ['hehe', 2, 'wang', ['wanggang', 'xudong']]]

# 取大于等于3，小于5
print(li[3:5])
---
['age', ['hehe', 2, 'wang', ['wanggang', 'xudong']]]

支持for循环，while循环，break,continue

for item in li:
    print(item)
---
1
12
9
age
['hehe', 2, 'wang', ['wanggang', 'xudong']]
end

列表中的元素是可以被修改的，字符串不能被修改

li = [1,12,9,"age",["hehe",2,"wang",["wanggang","xudong"]],"end"]
li[1] = 250
print(li)
---
[1, 250, 9, 'age', ['hehe', 2, 'wang', ['wanggang', 'xudong']], 'end']
# 切片修改
li[1:3] = [250,500]
print(li)
---
[1, 250, 500, 'age', ['hehe', 2, 'wang', ['wanggang', 'xudong']], 'end']

可以被删除

del li[1]
print(li)
---
[1, 9, 'age', ['hehe', 2, 'wang', ['wanggang', 'xudong']], 'end']

# 通过切片删除
li = [1,12,9,"age",["hehe",2,"wang",["wanggang","xudong"]],"end"]

del li[4:-1]
print(li)
---
[1, 12, 9, 'age', 'end']

数字转字符串str()
字符串转数字int()

a = 123
int(a)
a = 123
str(a)

字符串转列表

a = "yangyajun"
print(list(a))
---
['y', 'a', 'n', 'g', 'y', 'a', 'j', 'u', 'n']

append追加

def append(self,p_object)
li = [11,22,33,44]
v = li.append(5)
print(v)
---
None
# 在原来值后追加
print(li)
---
[11,22,33,44,5]

清空

li.clear()
print(li)
---
[]

copy复制,浅拷贝

v = li.copy()
print(v)
---
[11,22,33,44]

计数count,计算元素出现的次数

v = li.count(22)
print(v)
---
2

iterable迭代，必须传一个可迭代对象

li = [11,22,33,22,44]
li.extend([9898,"不得了"])
print(li)
---
[11, 22, 33, 22, 44, 9898, '不得了']

index,根据值找索引（位置）

def index(self,value,start=None, stop=None):...
v = li.index(33)
print(v)
---
1

insert,根据指定位置（索引位置）插入元素

li = [11,22,33,22,44]
v = li.insert(0,99)
print(li)
---
[99, 11, 22, 33, 22, 44]

pop,默认把最后一个元素删除,并获取被删除的值

def pop(self,index=None)
li.pop()
print(li,v)
---
[11, 22, 33, 22] 44

# 根据索引的位置删除值，并获取,如果没有指定索引，默认是最后一个
v = li.pop(1)
print(li,v)
---
[11, 33, 22, 44] 22

remove,删除列中中指定值，左边优先

li.remove(22)
print(li,v)
---
[22, 33, 22, 44] None

将当前列表进行反转

li = [11,22,33,22,44]
li.reverse()
print(li)
---
[44, 22, 33, 22, 11]

排序

li = [11,44,22,33,22]
li.sort()
print(li)
---
[11, 22, 22, 33, 44]
# 从大到小排序
li.sort(revers=True)
---
[44, 33, 22, 22, 11]