6.9 列表元素的删除操作

 

 

#  remove（）

 

lst1=[10,20,30,40,10,60,70,80,90,100]
lst1.remove(20)  #移除对应元素
lst1.remove(10)  #移除对应元素，如有相同元素移除第一个
print(lst1)
lst1.remove(200) #没有该元素就报错，ValueError

E:\PycharmProjects\pythonProject\venv\Scripts\python.exe E:/PycharmProjects/pythonProject/demon1/demo4.py
[30, 40, 10, 60, 70, 80, 90, 100]
Traceback (most recent call last):
  File "E:/PycharmProjects/pythonProject/demon1/demo4.py", line 5, in <module>
    lst1.remove(200) #没有该元素就报错，ValueError
ValueError: list.remove(x): x not in list

进程已结束,退出代码1

#  pop（）

 

lst2=[10,20,30,40,10,60,70,80,90,100,1000]
lst2.pop(1) #删除一个指定索引位置上的元素
lst2.pop()  #不指定索引删除最后一个元素
print(lst2)

 

E:\PycharmProjects\pythonProject\venv\Scripts\python.exe E:/PycharmProjects/pythonProject/demon1/demo4.py
[10, 30, 40, 10, 60, 70, 80, 90, 100]

进程已结束,退出代码0

#切片------------注意: 将产生新的列表对象

 

lst1=[10,20,30,40,10,60,70,80,90,100,1000]
lst3=[10,20,30,40,10,60,70,80,90,100,1001]
lst2=lst1[1:3] #删除一个指定索引位置范围外的所有元素，产生新的列表对象
##注意切片产生了新的列表对象lst2
print(lst2)
print(lst1)
##如何不产生新的列表对象
lst3[1:3]=[]  #用空列表进行替换
print(lst3)

 

E:\PycharmProjects\pythonProject\venv\Scripts\python.exe E:/PycharmProjects/pythonProject/demon1/demo4.py
[20, 30]
[10, 20, 30, 40, 10, 60, 70, 80, 90, 100, 1000]
[10, 40, 10, 60, 70, 80, 90, 100, 1001]

#  clear（）和 del  lst  清空和删除列表对象

 

lst1=[10,20,30,40,10,60,70,80,90,100,1000]
lst1.clear()##清空列表元素
print(lst1)

 

E:\PycharmProjects\pythonProject\venv\Scripts\python.exe E:/PycharmProjects/pythonProject/demon1/demo4.py
[]

lst1=[10,20,30,40,10,60,70,80,90,100,1000]
del lst1
print(lst1)

NameError: name 'lst1' is not defined