Python-数据类型之列表

三：列表

3.1  列表的定义语法

中括号，已逗号为分割，可以方任意得数据类型，甚至是对象

li = ['wangys','lala',123,[1,2,3],{'name':'wangys'}]

3.2 取单个元素，取出的是原数据类型

li = ['wangys','lala',123,[1,2,3],{'name':'wangys'}]
l1=li[0]
print(l1,type(l1))
l2=li[2]
print(l2,type(l2))
l3=li[3]
print(l3,type(l3))

3.3 取多个元素，取出的是列表类型

li = ['wangys','lala',123,[1,2,3],{'name':'wangys'}]
l4=li[0:2]
print(l4,type(l4))

3.4  增加元素

增加元素有三种操作

3.4.1 append 在末尾增加

li = ['wangys','gongzhu']
li.append('caomei')
li.append('1')
print(li)

# 需求： 员工列表，往员工列表里添加员工，可以持续添加，当输入q时退出

people = ['wangys','huisz']
flag = True
while flag:
    add_people = input("请输入员工姓名：").strip()
    if add_people.upper() == 'Q':
        flag = False
    else:
        people.append(add_people)
    print(people)

3.4.2  insert 按照索引进行插入

name = ['wangys','chaoyf']
name.insert(1,'huisz')
print(name)

3.4.3 extend 将可迭代对象插入到列表的末尾，插入的是可迭代对象的每个元素

整型是不可迭代对象

name = ['wangys','chaoyf']
name.extend('lala')
print(name)
name.extend([1,2,3])
print(name)

3.5 删除元素

3.5.1 pop 

1: pop 有返回值，该返回值是被删除的数据

2：按索引删除

3：不指定索引，把最后一个元素删除

name = ['wangys','lala']
delete_name = name.pop()
print(delete_name,name)

name = ["wangys","haha"]
name.pop(0)
print(name)

name = ["wangys","hehe"]
print(name.pop())

3.5.2 按照元素去删除

name = ['wangys','dede']
name.remove('dede')
print(name)

3.5.3 清空列表

name = ["wangys","dsad"]
name.clear()
print(name)

3.5.4 删除列表

name = ['wangys']
del name
print(name)

3.5.5 切片删除

name = ['wangys',"lala",'haha']
del name[1:]
print(name)

3.6 改元素

3.6.1 单个元素改

是按照索引修改，插入什么就是什么，单个元素插入

name = ["wangys","haha"]
name[1] = 'xiaogongzhu'
print(name)

name = ["wangys","sdfsdf"]
name[1] = ['xiaogongzhu','chaomei']
print(name)

3.6.2 切片的方式插入

1：首先把切片元素删除

2：将添加元素以迭代方式插入

name = ["wangys","lala"]
name[1:] = 'haha'
print(name)

name = ["wangys","lala"]
name[1:] = ["xiaogongzhu","chaomei"]
print(name)

3.7 元素查找

3.7.1 查看所有元素

name = ['wangys','xiaogongzhu']
for i in name:
    print(i)

3.7.2 查看前两个元素

查出来的是一个列表

name = ['wangys','xiaogongzhu']
print(name[:2])

3.8 ：列表的一些公共方法

3.8.1  查看列表的长度

wangys_info = ["wangys",23,'male']
l = len(wangys_info)
print(l)

3.8.2  查看列表中某元素的个数

num = [1,2,3,1,2,4]
CountOf1=num.count(1)
print(CountOf1)

3.8.3  根据元素看索引

如果元素不存在报错

wangys_info = ["wangys",23,'male']
print(wangys_info.index('male'))
print(wangys_info.index('malea'))

3.8.4  排序

正向排序

num = [3,6,2,5,4]
num.sort()
print(num)

反向排序

num = [3,6,2,5,4]
num.sort(reverse=True)
print(num)

3.8.5 列表反转

num = [3,6,2,5,4]
num.reverse()
print(num)

3.9 ：列表的嵌套

wangys_info = ['wangys',23,'male',['sing','play',22],25]

取出wangys里的a

wangys_info = ['wangys',23,'male',['sing','play',22],25]
print(wangys_info[0][1])

将列表的第一个元素大写并替换之前的元素

wangys_info = ['wangys',23,'male',['sing','play',22],25]
wangys_info[0] = wangys_info[0].capitalize()
print(wangys_info)

将王诚替换为王永胜

wangys_info = ['wangys',23,'王诚',['sing','play',22],25]
wangys_info[2] = wangys_info[2].replace('诚','永胜')
print(wangys_info)

wangys_info = ['wangys',23,'王诚',['sing','play',22],25]
wangys_info[3][1] = wangys_info[3][1].upper()
print(wangys_info)