第二周 第七节 列表的使用

Posted 2021-02-16 googlewang

name=["zhangyang","guyun","xiangpeng"]
print(name[0],name[2])

zhangyang xiangpeng

name=["zhangyang","guyun","xiangpeng"]　
print(name[1:3]) #切片，起始位置包括，结束位置不包括，顾头不顾尾
"zhangyang","guyun","xiangpeng"

　　

name=["zhangyang","guyun","xiangpeng"]
print(name[-1])#取最后一个，从右开始数，负号代表从右开始的方向，

xiangpeng

　　

 

name=["zhangyang","guyun","xiangpeng"]
print(name[-2])
guyun

　　

 

取最后两个值
name=["zhangyang","guyun","xiangpeng","xia"]
print(name[-1:-3])
取值是空
[]
因为切片是从左向右数，这里是-的，所以写的要从右往左数

　　

 

取最后两个值
name=["zhangyang","guyun","xiangpeng","xia"]
print(name[-3:-1])
#要最后两个，冒号左边从哪里开始，右边是。负号是从右边开始，顾首不顾尾

[‘guyun‘, ‘xiangpeng‘]

　　

 

 

name=["zhangyang","guyun","xiangpeng","xia"]
print(name[-2:])
#要最后两个，冒号左边从哪里开始，右边是

[‘xiangpeng‘, ‘xia‘] 把-1省略掉才能取出来

　　

 

 

name=["zhangyang","guyun","xiangpeng","xia"]
print(name[0:3]) //可以省略0 print(name[:3])

[‘zhangyang‘, ‘guyun‘, ‘xiangpeng‘] 顾首不顾尾

　　

 

追加：
name=["zhangyang","guyun","xiangpeng","xia"]
name.append("lei")
print(name)


[‘zhangyang‘, ‘guyun‘, ‘xiangpeng‘, ‘xia‘, ‘lei‘]

　　

 

插入：
name=["zhangyang","guyun","xiangpeng","xia"]
name.append("lei")
name.insert(1,"chen")#chen的位置就是1
name.insert(3,"xin") #插入位置，每次只能插入一个
print(name)

[‘zhangyang‘, ‘chen‘, ‘guyun‘, ‘xin‘, ‘xiangpeng‘, ‘xia‘, ‘lei‘]

　　

 

 

 

 

 

修改

name=["zhangyang","guyun","xiangpeng","xia"]
name[2]="xied"
print(name)


[‘zhangyang‘, ‘guyun‘, ‘xied‘, ‘xia‘]

　　

 

删除：
法1
name=["zhangyang","guyun","xiangpeng","xia"]
name.remove("xia")
print(name)


[‘zhangyang‘, ‘guyun‘, ‘xiangpeng‘]

　　

 

法2
name=["zhangyang","guyun","xiangpeng","xia"]
del name[3]
print(name)

[‘zhangyang‘, ‘guyun‘, ‘xiangpeng‘]

　　

 

 

name=["zhangyang","guyun","xiangpeng","xia"]
name.pop() 不输下标，代表删除最后一个
print(name)
[‘zhangyang‘, ‘guyun‘, ‘xiangpeng‘]

　　

 

name=["zhangyang","guyun","xiangpeng","xia"]
name.pop(2) 删除指定位置
print(name)

[‘zhangyang‘, ‘guyun‘, ‘xia‘]

　　

 

 

 

name=["zhangyang","guyun","xiangpeng","xia"]
print(name.index("guyun"))索引
1

 

　　

 

name=["zhangyang","guyun","xiangpeng","xia"]
print(name[name.index("guyun")])

guyun 把所在的位置的名字打印出来

　　

 

 

name=["zhangyang","guyun","guyun","xiangpeng","xia"]
print(name.count("guyun")) #统计有多少个guyun

2

　　

 

 

 

name=["zhangyang","guyun","guyun","xiangpeng","xia"]
name.clear() 清除
print(name)
[]

　　

 

 

name=["zhangyang","guyun","guyun","xiangpeng","xia"]
name.reverse() 翻转
print(name)


[‘xia‘, ‘xiangpeng‘, ‘guyun‘, ‘guyun‘, ‘zhangyang‘]

　　

 

 

name=["zhangyang","guyun","guyun","xiangpeng","xia"]
name.sort()排序
print(name)

[‘guyun‘, ‘guyun‘, ‘xia‘, ‘xiangpeng‘, ‘zhangyang‘]

　　

 

 

name=["zhangyang","guyun","guyun","xiangpeng","xia"]
name2=[1,2,3,4]
name.extend(name2) 合并，并且name2还存在
print(name)

[‘zhangyang‘, ‘guyun‘, ‘guyun‘, ‘xiangpeng‘, ‘xia‘, 1, 2, 3, 4] [1, 2, 3, 4]

　　

 

 

name=["zhangyang","guyun","guyun","xiangpeng","xia"]
name2=name.copy()复制
print(name)
print(name2)


[‘zhangyang‘, ‘guyun‘, ‘guyun‘, ‘xiangpeng‘, ‘xia‘]
[‘zhangyang‘, ‘guyun‘, ‘guyun‘, ‘xiangpeng‘, ‘xia‘]