列表数据类型内置方法

列表数据类型内置方法

1.作用

描诉多个值,比如爱好

2.定义方式

hobby_list = ['play', 'swim', 'dancing', '666']
print(hobby_list)

3.内置方法

优先掌握

1.索引取值

hobby_lsit=['play','dance','jump','666']
print(hobby_lsit[-1])
hobby_lsit[-1]='233'
print(hobby_lsit[-1])

666,233

2.切片

hobby_lsit=['play','dance','jump','666']
print(hobby_lsit[:])
print(hobby_lsit[::-1])

['play', 'dance', 'jump', '666']
['666', 'jump', 'dance', 'play']

3.长度

hobby_lsit=['play','dance','jump','666']
print(len(hobby_lsit))

4

4.in/not in

hobby_list = ['play', 'swim', 'dancing', '666']
print('play' in hobby_list)  

True

5.for循环

hobby_list=['play','dance','jump','666']
for hobby in hobby_list:
    print(hobby)

play
dance
jump
666

6.del删除

hobby_list=['play','dance','jump','666']
del hobby_list[-1]
print(hobby_list)

['play', 'dance', 'jump']

7.append() 追加

hobby_lsit=['play','dance','jump','666']
hobby_lsit.append('dapao-->sword')
print(hobby_lsit)

['play', 'dance', 'jump', '666', 'dapao-->sword']

需要掌握

1.count 对列表内某一个元素计数

hobby_lsit=['play','dance','jump','666',666,666]
print(hobby_lsit.count(666))

2

2.extend 扩展列表

hobby_lsit=['play','dance','jump','666',666,666]
hobby_lsit.extend([1,2,3,4])
print(hobby_lsit)

['play', 'dance', 'jump', '666', 666, 666, 1, 2, 3, 4]

3.clear 清除

hobby_lsit=['play','dance','jump','666',666,666]
hobby_lsit.clear()
print(hobby_lsit)

[]

4.copy 复制列表

hobby_list=['play','dance','jump','666',666,666]
hobby_list_2=hobby_list.copy()
hobby_list[-1]='233'
print(hobby_list)
print(hobby_list_2)

['play', 'dance', 'jump', '666', 666, '233']
['play', 'dance', 'jump', '666', 666, 666]

5.pop 删除,默认删除最后一个

hobby_list=['play','dance','jump','666',666,666]
hobby_list.pop()
print(hobby_list)

['play', 'dance', 'jump', '666', 666]

6.index 索引

hobby_list=['play','dance','jump','666',666,666]
print(hobby_list.index('play'))
print(hobby_list.index('jump',1,3))  #索引1-3内有没有该值

0

2

7.insert 插入

hobby_list=['play','dance','jump','666',666,666]
hobby_list.insert(0,'1')
print(hobby_list)

'1', 'play', 'dance', 'jump', '666', 666, 666]

8.移除 remove

hobby_list=['play','dance','jump','666',666,666]
hobby_list.insert(0,'1')
print(hobby_list)
hobby_list.remove('1')
print(hobby_list)

['1', 'play', 'dance', 'jump', '666', 666, 666]
['play', 'dance', 'jump', '666', 666, 666]

9.反转 reverse

hobby_list=['play','dance','jump','666',666,666]
hobby_list.insert(0,'1')
print(hobby_list)
hobby_list.reverse()
print(hobby_list)

['1', 'play', 'dance', 'jump', '666', 666, 666]
[666, 666, '666', 'jump', 'dance', 'play', '1']

10.sort 排序 使用sort列表的元素必须是同类型的

name_list = ['aden','nick', 'jason', 'tank', 'sean']
name_list.sort()
print(name_list)

['aden', 'jason', 'nick', 'sean', 'tank']

4.存一个值还是多个值

多个值

5.有序or无序

有序

6.可变or不可变

可变

lis = [12, 14]
print(id(lis))
lis.append('l1')
print(id(lis))

2379100691848
2379100691848