python基本数据类型列表、元组、字典、集合

文章目录

• 1、列表
• 2、元组
• 3、字典
• 3.1 定义字典
• 3.2 添加
• 3.3 删除
• 3.4 查询
• 3.5 修改
• 3.6 遍历
• 3.6.1 遍历键和值
• 3.6.2 只遍历键
• 3.6.3 只遍历值

1、列表

lists = ['a','b','c']
print(lists)

lists.append('d')
print(lists)
print(len(lists))

lists.insert(0,"mm")
print(lists)

lists.pop()     #pop（）删除尾部元素
print(lists)

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
['a', 'b', 'c']
['a', 'b', 'c', 'd']
4
['mm', 'a', 'b', 'c', 'd']
['mm', 'a', 'b', 'c']

Process finished with exit code 0

2、元组

和列表相比缺点是一旦建之后就无法修改，无法插入删除，只可以访问

tuples = ('tupleA','tupleB')
print(tuples[0])

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
tupleA

Process finished with exit code 0

3、字典

key和values可以为任意类型

3.1 定义字典

score = {'guanyu':95,'zhangfei':96}
print(score)

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
{'guanyu': 95, 'zhangfei': 96}

Process finished with exit code 0

3.2 添加

score['zhaoyun'] = 98
print(score)

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
{'guanyu': 95, 'zhangfei': 96, 'zhaoyun': 98}

Process finished with exit code 0

3.3 删除

score.pop('zhangfei')
print(score)

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
{'guanyu': 95, 'zhaoyun': 98}

Process finished with exit code 0

3.4 查询

#查看key是否存在
print('guanyu') in score

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
guanyu

Process finished with exit code 0

#查询key对应的值
print(score.get('guanyu'))

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
95

Process finished with exit code 0

3.5 修改

#当值不存在时赋一个值为99
print(score.get('yase',99))

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
99

Process finished with exit code 0

3.6 遍历

3.6.1 遍历键和值

score = {'guanyu':95,'zhangfei':96}
for name,grade in score.items():
print(name+':'+str(grade))

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
guanyu:95
zhangfei:96

Process finished with exit code 0

3.6.2 只遍历键

for name in score.keys():
print(name)

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
guanyu
zhaoyun

Process finished with exit code 0

3.6.3 只遍历值

for grade in score.values():
print(grade)

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
95
98

Process finished with exit code 0

3.7 基于字典的模糊查找

模糊查找就是说输入一个key中的一部分，而非整个key，来进行相对应值的查找。

score = {'guanyu':95,'zhangfei':96,'zhaoyun':80,'songjiang':76}
while (True):
n=input("please enter the name of people:")
for name,grade in score.items():
if name.startswith(n):
print(name+':'+str(grade))
answer=input("wanna quit the game? y/n:")
if answer=='y':
break

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
please enter the name of people:g
guanyu:95
wanna quit the game? y/n:y

Process finished with exit code 0

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
please enter the name of people:song
songjiang:76
wanna quit the game? y/n:n
please enter the name of people:zha
zhangfei:96
zhaoyun:80
wanna quit the game? y/n:y

Process finished with exit code 0

参数介绍:

startswith(str, beg,end)

str – 检测的字符串。
beg – 可选参数用于设置字符串检测的起始位置。
end – 可选参数用于设置字符串检测的结束位置。

4、集合

和字典类似，但是它只有key，没有value，集合中不能包含重复元素，集合是无序的，不支持排序和索引

s = set(['a', 'b', 'c'])
s.add('d')
s.remove('b')
print(s)
print('c' in s)

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
{'c', 'a', 'd'}
True

Process finished with exit code 0

空集合的创建应该用set(),而不是{}，因为{}创建出来的默认为一个空字典。

a=set()
a.add('m')
print(a)

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
{'m'}

Process finished with exit code 0

求交并差集：

a={1,2,3,4}
b={3,4,5,6}
print("a和b的交集为"+str(a&b))
print("a和b的并集为"+str(a|b))
print("a和b的差集为"+str(a-b))

结果：

C:\Users\Admin\Anaconda3\python.exe D:/winterVocation/GeekTime/day1.py
a和b的交集为{3, 4}
a和b的并集为{1, 2, 3, 4, 5, 6}
a和b的差集为{1, 2}

Process finished with exit code 0