列表数据类型内置方法

目录

• 列表
  • 1、作用：描述多个值,比如爱好
  • 2、定义方式：
  • 3、内置方法
    • 3.1 优先掌握
      • 1、索引取值
      • 2、切片
      • 3、长度
      • 4. in/not in
      • 5. for 循环
      • 6. del删除
      • 7. append() # 追加
    • 3.2 需要掌握
      • 1、count(对列表内的某一个元素计数)
      • 2、extend（扩展列表：ctrl+鼠标左键进入源码模式）
      • 3、clear清除列表
      • 4、copy复制列表
      • 5、pop删除
      • 6、index
      • 7、insert插入
      • 8、remove移除
      • 9、reverse反转

列表

1、作用：描述多个值,比如爱好

2、定义方式：

obby_list = ['play', 'swimming', 'dancing', '666']

3、内置方法

3.1 优先掌握

1、索引取值

hobby_list = ['swimming','play','dance','singing','paino']
print(hobby_list)
hobby_list[1] = 'game'#修改索引
print(hobby_list)
print(1,hobby_list[2])#1表示给所取的元素添加一个序号
print(hobby_list[0])

输出结果：
['swimming', 'play', 'dance', 'singing', 'paino']
['swimming', 'game', 'dance', 'singing', 'paino']
1 dance
swimming

2、切片

hobby_list = ['swimming','play','dance','singing','paino']
print(hobby_list[:])
print(hobby_list[::-1])

输出结果：
['swimming', 'play', 'dance', 'singing', 'paino']
['paino', 'singing', 'dance', 'play', 'swimming']

3、长度

print(len(hobby_list))

4. in/not in

hobby_list = ['play', 'swimming', 'dancing', '666']
print('play' in hobby_list)
输出结果：
True

5. for 循环

hobby_list = ['play', 'swimming', 'dancing', '666']
for hobby in hobby_list:
    print(hobby)
输出结果：
swimming
play
dance
singing
paino

6. del删除

hobby_list = ['play', 'swimming', 'dancing', '666']
del hobby_list[-1]#从右到左删除第一个
print(hobby_list)
输出结果：
['play', 'swimming', 'dancing']

7. append() # 追加

hobby_list = ['play', 'swimming', 'dancing', '666']
hobby_list.append('追加任意字符')#默认追加在最后
print(hobby_list)
输出结果：
['play', 'swimming', 'dancing', '666', '追加任意字符']

3.2 需要掌握

1、count(对列表内的某一个元素计数)

hobby_list = ['play', 'swimming', 'dancing', '666', 666, '666']
print(hobby_list.count('666'))
输出结果：
2

2、extend（扩展列表：ctrl+鼠标左键进入源码模式）

hobby_list = ['play', 'swimming', 'dancing', '666', 666, '666']
hobby_list.extend([1,2,3])
print(hobby_list)
输出结果:
['play', 'swimming', 'dancing', '666', 666, '666', 1, 2, 3]

3、clear清除列表

hobby_list = ['play', 'swimming', 'dancing', '666', 666, '666']
hobby_list.clear()
print(hobby_list)
输出结果：
[]

4、copy复制列表

hobby_list = ['play', 'swimming', 'dancing', '666', 666, '666']
print(hobby_list)
hobby_list1 = hobby_list.copy()
print(hobby_list1)
输出结果：
['play', 'swimming', 'dancing', '666', 666, '666']
['play', 'swimming', 'dancing', '666', 666, '666']

5、pop删除

hobby_list = ['play', 'swimming', 'dancing', '666', 345, '123']
print(hobby_list)

hobby_list.pop()
print(hobby_list)#默认删除最后一个

hobby_list.pop(2)
print(hobby_list)#根据索引删除第3个
输出结果：
['play', 'swimming', 'dancing', '666', 345, '123']
['play', 'swimming', 'dancing', '666', 345]
['play', 'swimming', '666', 345]

6、index

hobby_list = ['play', 'swimming', 'dancing', '666', 345, '123']
print(hobby_list)

print(hobby_list.index('666'))  # 索引
print(hobby_list.index('666', 1, 4))  # 索引2-4内有没有该值，有则返回对应值的索引，没有则报错

7、insert插入

hobby_list = ['play', 'swimming', 'dancing', '666', 345, '123']
print(hobby_list)
hobby_list.insert(0, '1')  # 插入
print(hobby_list)
输出结果：
['play', 'swimming', 'dancing', '666', 345, '123']
['1', 'play', 'swimming', 'dancing', '666', 345, '123']

8、remove移除

hobby_list = ['play', 'swimming', 'dancing', '666', 345, '123']
print(hobby_list)
hobby_list.remove('666')
print(hobby_list)
输出结果：
['play', 'swimming', 'dancing', '666', 345, '123']
['play', 'swimming', 'dancing', 345, '123']

9、reverse反转

hobby_list = ['play', 'swimming', 'dancing', '666', 345, '123']
hobby_list.reverse()
print(hobby_list)
输出结果：
['123', 345, '666', 'dancing', 'swimming', 'play']