4.1列表类型的内置方法(list)
-
用途:多个装备,多个爱好,多门课程,甚至多个朋友
-
定义:[]内可以有多个任意类型的值,逗号分隔 元素
-
存一个值还是多个值: 多个值
-
有序or无序 有序
4.2常用操作+内置方法:
4.2.1优先掌握
-
按索引取值
-
切片
-
长度len
-
成员运算in和not in
-
追加append
-
删除del
-
循环
-
按索引取值
hobby_list = ['play', 'swimming', 'dancing', 'football']
print(hobby_list[2])
运行结果:
dancing -
切片
hobby_list = ['play', 'swimming', 'dancing', 'football']
print(hobby_list[:])
print(hobby_list[::-1]) # 从右到左
运行结果:
['play', 'swimming', 'dancing', 'football']
['football', 'dancing', 'swimming', 'play'] -
长度len
hobby_list = ['play', 'swimming', 'dancing', 'football']
print(len(hobby_list))
运行结果:
4 -
in 和not in
hobby_list = ['play', 'swimming', 'dancing', 'football']
print('play' in hobby_list) # True -
for 循环
hobby_list = ['play', 'swimming', 'dancing', 'football']
for hobby in hobby_list:
print(hobby)
运行结果:
play
swimming
dancing
football -
del删除
hobby_list = ['play', 'swimming', 'dancing', 'football']
del hobby_list[-1]
print(hobby_list)
运行结果:
['play', 'swimming', 'dancing']
-
appeend追加
hobby_list = ['play', 'swimming', 'dancing', 'football']
hobby_list.append('dapao-->piao')
print(hobby_list)
运行结果:
['play', 'swimming', 'dancing', 'football', 'dapao-->piao']
4.2.2需要掌握
-
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'))
运行结果:
2 -
extend 扩展列表
hobby_list = ['play', 'swimming', 'dancing', '666', 666, '666']
hobby_list.extend([1, 2, 3, 4])
print(hobby_list)
运行结果:
['play', 'swimming', 'dancing', '666', 666, '666', 1, 2, 3, 4] -
clear 清除
hobby_list = ['play', 'swimming', 'dancing', '666', 666, '666']
hobby_list.clear()
print(hobby_list)
运行结果:
[] -
copy 复制列表
hobby_list = ['play', 'swimming', 'dancing', '666', 666, '666']
hobby_list2 = hobby_list.copy()
print(hobby_list2)
运行结果:
['play', 'swimming', 'dancing', '666', 666, '666'] -
pop 删除,默认删除最后一个
hobby_list = ['play', 'swimming', 'dancing', '666', 666, '666']
hobby_list.pop()
print(hobby_list)
运行结果:
['play', 'swimming', 'dancing', '666', 666] -
index索引
print(hobby_list.index('play'))
运行结果:
0 -
insert 插入
hobby_list = ['play', 'swimming', 'dancing', '666', 666, '666']
hobby_list.insert(0, '1')#表示插入的位置
print(hobby_list)
运行结果:
['1', 'play', 'swimming', 'dancing', '666', 666, '666'] -
remove 移除
hobby_list = ['play', 'swimming', 'dancing', '666', 666, '666']
hobby_list.insert(0, '1')
print(hobby_list)
hobby_list.remove('1')
print(hobby_list)
运行结果:
['1', 'play', 'swimming', 'dancing', '666', 666, '666']
['play', 'swimming', 'dancing', '666', 666, '666'] -
reverse 反转
hobby_list = ['play', 'swimming', 'dancing', '666', 666, '666']
hobby_list.reverse()
print(hobby_list)
运行结果:
['666', 666, '666', 'dancing', 'swimming', 'play']
五、元祖数据类型内置方法
-
定义:定义:()内可以有多个任意类型的值,逗号分隔 元素
-
内置方法:
元祖和列表一模一样,但是元祖无法修改,元祖在定义那一刻他的元素个数以及元素的值全部固定了
-
存一个值还是多个值 多个值
-
有序or无序 有序
-
可变or不可变(重点) 压根没有这一说
六、字典数据类型内置方法
6.1字典类型的内置方法
-
作用:对于值添加描述信息使用它
-
定义方法:用{}以逗号隔开加入键值对key:value。
-
存一个值还是多个值:
多个值
-
有序or无序:
无序
-
可变or不可变(重点):
可变
6.2 内置方法
6.2.1 优先掌握
-
按key存取值:可存可取
info_dict = {'name': 'wangdapao', 'age': 18, 'height': 120, 'gender': 'female', 'hobby_list': ['dapao', '666', '233']}
print(info_dict['name'])
运行结果:
wangdapao -
长度len
info_dict = {'name': 'wangdapao', 'age': 18, 'height': 120, 'gender': 'female', 'hobby_list': ['dapao', '666', '233']}
print(len(info_dict))
运行结果:
5 -
成员运算in和not in
info_dict = {'name': 'wangdapao', 'age': 18, 'height': 120, 'gender': 'female', 'hobby_list': ['dapao', '666', '233']}
print('name' in info_dict)
运行结果:
True -
删除del
del info_dict['name']
print(info_dict)
运行结果:
{'age': 18, 'height': 120, 'gender': 'female', 'hobby_list': ['dapao', '666', '233']} -
键keys()、值values()、键值对items()
print(list(info_dict.keys()))#list
print(list(info_dict.values())#list
print(list(info_dict.items())) #list
运行结果:
['name', 'age', 'height', 'gender', 'hobby_list']
['wangdapao', 18, 120, 'female', ['dapao', '666', '233']]
[('name', 'wangdapao'), ('age', 18), ('height', 120), ('gender', 'female'), ('hobby_list', ['dapao', '666', '233'])]
-
循环
for i in info_dict.values():
print(i)
运行结果:
wangdapao
18
120
female
['dapao', '666', '233']for i in info_dict.items():
print(i)
运行结果:
('name', 'wangdapao')
('age', 18)
('height', 120)
('gender', 'female')
('hobby_list', ['dapao', '666', '233'])for k, v in info_dict.items(): print(k, v)
运行结果:
name wangdapao
age 18
height 120
gender female
hobby_list ['dapao', '666', '233']
6.2.2需要掌握
-
get
dic3 = dict.fromkeys(['name','age','sex'],None)
print(dic3)
print(f"dic3.setdefault('name'):{dic3.setdefault('name',3)}")
print(f"dic3.get('name'):{dic3.get('name',3)}")
运行结果:
dic3.get('name'):None -
update
dic1 = {'name': 'wangdapao', 'age': 18, 'height': 120, 'gender': 'female', 'hobby_list': ['dapao', '666', '233']}
dic2 = {'weight':180}
dic1.update(dic2)
print(dic1)
运行结果:
{'name': 'wangdapao', 'age': 18, 'height': 120, 'gender': 'female', 'hobby_list': ['dapao', '666', '233'], 'weight': 180}
-
fromkeys(由dict.出来,快速造一个字典)
dic3=dict.fromkeys(['name','age','sex'],None)
print(dic3)
运行结果:
{'name': None, 'age': None, 'sex': None} -
setdefault
ic3 = dict.fromkeys(['name','age','sex'],None)
print(dic3)
print(f"dic3.setdefault('name'):{dic3.setdefault('name',3)}")
运行结果:
dic3.setdefault('name'):None
七、集合类型内置方法
7.1集合类型内置方法(set)
集合可以理解成一个集合体。
-
用途:用于关系运算的集合体,由于集合内的元素无序且集合元素不可重复,因此集合可以去重,但是去重后会打乱原来的顺序。
-
定义:{}内用逗号分隔开多个元素,每个元素必须是不可变类型。
-
存一个值or多个值:多个值,且值为不可变类型。
-
有序or无序:无序
7.2常用操作+内置方法:
7.2.1优先掌握
-
长度len
s = {1,'2','3','a'}
print(len(s))#4 -
成员运算in和not in
s = {1,'2','3','a'}
print(1 in s)#True -
|并集、union
pythoners = {'jason', 'nick', 'tank', 'sean'}
linuxers = {'nick', 'egon', 'kevin'}
print(pythoners|linuxers)
运行结果:
{'egon', 'nick', 'kevin', 'sean', 'jason', 'tank'} -
&交集、intersection
pythoners = {'jason', 'nick', 'tank', 'sean'}
linuxers = {'nick', 'egon', 'kevin'}
print(pythoners&linuxers)
运行结果:
{'nick'}
-
-差集、difference
pythoners = {'jason', 'nick', 'tank', 'sean'}
linuxers = {'nick', 'egon', 'kevin'}
print(pythoners-linuxers)
运行结果:
{'sean', 'jason', 'tank'} -
^对称差集、symmetric_difference
pythoners = {'jason', 'nick', 'tank', 'sean'}
linuxers = {'nick', 'egon', 'kevin'}
print(pythoners^linuxers)
运行结果:
{'kevin', 'egon', 'sean', 'jason', 'tank'} -
==
pythoners = {'jason', 'nick', 'tank', 'sean'}
linuxers = {'nick', 'egon', 'kevin'}
print(pythoners==linuxers)
运行结果:
False -
父集:>、>= 、issuperset
pythoners = {'jason', 'nick', 'tank', 'sean'}
linuxers = {'nick', 'egon', 'kevin'}
print(pythoners>linuxers)
print(pythoners>=linuxers)
运行结果:
False
False -
子集:<、<= 、issubset
pythoners = {'jason', 'nick', 'tank', 'sean'}
linuxers = {'nick', 'egon', 'kevin'}
print(pythoners<linuxers)
print(pythoners<=linuxers)
运行结果:
False
False
7.2.2 需要掌握
-
add增加
s = {1,2,3,'a'}
s.add(4)
print(s)
运行结果:
{1, 2, 3, 4, 'a'} -
remove移除(如果没有就报错)
s = {1,2,3,'a'}
s.remove(3)
print(s)
运行结果:
{1, 2, 'a'} -
difference_update
pythoners = {'jason', 'nick', 'tank', 'sean'}
linuxers = {'nick', 'egon', 'kevin'}
pythoners.difference_update(linuxers)
print(pythoners)
运行结果:
{'tank', 'sean', 'jason'} -
discard(如果没有不会报错)
s = {1,2,3,'a'}
s.discard(4)
print(s.discard(4))
运行结果:
None -
isdisjoint
pythoners = {'jason', 'nick', 'tank', 'sean'}
linuxers = {'nick', 'egon', 'kevin'}
print(pythoners.isdisjoint(linuxers))
运行结果:
False
-
pop随机删除
pythoners = {'jason', 'nick', 'tank', 'sean'}
pythoners.pop()
print(pythoners)
运行结果:
{'nick', 'jason', 'tank'} -
clear清空
pythoners = {'jason', 'nick', 'tank', 'sean'}
pythoners.clear()
print(pythoners)
运行结果:
set() -
copy复制
pythoners = {'jason', 'nick', 'tank', 'sean'}
print(pythoners)
print(pythoners.copy())
运行结果:
'nick', 'jason', 'sean', 'tank'}
{'nick', 'jason', 'sean', 'tank'}
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