python中常用的内置方法

In [55]: min(2,3)                  //最小值
Out[55]: 2

In [56]: max(2,3)                //最大值
Out[56]: 3

In [57]: sum(range(1,101))               //求和
Out[57]: 5050

In [58]: sum(range(1,101,2))
Out[58]: 2500

In [59]: sum(range(2,101,2))
Out[59]: 2550

枚举：返回索引值和对应的value值

for i,v in enumerate('hello'):
print(i,v)
运行结果：/home/kiosk/PycharmProjects/westos/westos/3_28/枚举.py
0 h
1 e
2 l
3 l
4 o

s1 = 'abc'
s2 = '123'
for i in zip(s1,s2):
print(i)
运行结果:
('a', '1')
('b', '2')
('c', '3')

for i in zip(s1,s2):
print(''.join(i))				//连接
print('-'.join(i))

元组的创建

元组(tuple): 元组本身是不可变数据类型，没有增删改查,可以存储任意数据类型

t = (1,2.3,True,'star')
print(t)
print(type(t))
运行结果:
(1, 2.3, True, 'star')
<class 'tuple'>

元组里面包含可变数据类型，可以间接修改元组内容

t1 = ([1,2,3],4)        //[1,2,3]列表
t1[0].append(4)
print(t1)

元组里如果只有一个元素的时候，后面要加逗号，否则数据类型不确定

t2 = ('hello',)
print(type(t2))

元组的特性

allowusers = (‘root’,‘westos’,‘redhat’)
allowpasswd = (‘123’,‘456’,‘789’)

print(allowusers[0])
print(allowusers[-1])
print(allowusers[1:])
print(allowusers[:-1])
print(allowusers[::-1])

print(allowusers * 3)

print(allowusers + ('linux','python'))   //注意添加的元素也是存在元组里的

print('westos' in allowusers)
print('westos' not in allowusers)

for user in allowusers:
print(user)

for index,user in enumerate(allowusers):      //枚举
print('第%d个白名单用户: %s' %(index+1,user))

for user,passwd in zip(allowusers,allowpasswd):
print(user,':',passwd)

元组的常用方法

t = (1,2.3,True,‘linux’)

print(t.count(‘linux’)) //打印元素出现次数
print(t.index(1)) //打印元素索引

元组的应用场景

t = ('westos',11,100)
name,age,score = t
print(name,age,score)

scores = (100,89,45,78,65)
scoresLi = list(scores)			//将元组转换为列表
scoresLi.sort()
print(scoresLi)

scores = sorted(scores)		//直接对元组排序
print(scores)

minscore,*middlescore,maxscore = scores     //可接收多个变量 *middlescore
print(minscore)
print(middlescore)
print(maxscore)