数据类型及字符编码 (须要从新修改)

1.数据类型:
　　数字(整型,长整型,浮点型,复数)
　　字符串:在介绍字符编码时介绍字节bytes类型
　　列表
　　元祖
　　字典
　　集合

2.整型 int
　　做用:年级/等级/身份证号等整型数字相关
　　定义: age=10　　本质上age=int(10)

 

十进制转成。。。进制 print(bin(13))    #将整型转变成二进制
print(oct(13))    #将整型转变成八进制
print(hex(13))    #将整型转变成十六进制

 

 

 

经常使用操做+内置方法

 

# 存一个值

# 不可变 # x=10 # print(id(x)) # x=11 # print(id(x))

 

 

 

　3. 浮点型 float 

　　做用:薪资/身高/体重等浮点数相关

salary=3000.3 #本质salary=float(3000.3)

 

 类型转换

print(float(10)) print(float(1.1)) print(float('1.1'))

 

 

 

 

4.字符串类型 str

　　做用:记录描述性值的状态,好比名字/性别等

msg='hello world' #msg=str('hello world')

 

 类型转换:能够把任意类型转成字符串类型

res1=str(10) res2=str(10.3) res3=str([1,2,3]) res4=str({'x':1}) #res4="{'x':1}"

 

 

 

*****经常使用操做+内置的方法

1.按索引取值(正向取+反向取):只能取

 

msg='hello world'

print(type(msg[0])) print(msg[-1]) msg[0]='H'

 

2.切片(顾头不顾尾,步长)

msg='hello world'
print(msg[0]+msg[1]+msg[2]) print(msg[0:5]) print(msg[0:5:2]) print(msg[0:]) print(msg[:]) print(msg[-1:-5:-1]) #-1 -2 -3 -4
print(msg[::-1]) #-1 -2 -3 -4

3.长度 len :统计的是字符的个数

4.成员运算 in 和 not in : 判断一个子字符是否存在于一个大字符串中

# msg='hello world' # print('ho' in msg) # print('ho' not in msg)

 

5.移除空白 strip : 移除字符串左右两边的某些字符

msg=' hello '

print(msg.strip(' ')) print(msg.strip()) print(msg) name=input('name>>>: ').strip() #name='egon'
pwd=input('password>>>: ').strip() if name == 'egon' and pwd == '123': print('login successfull') else: print('username or password error') msg='***h**ello**********'
print(msg.strip('*')) msg='*-=+h/ello*(_+__'
print(msg.strip('*-=+/(_'))

 

6.切分 split :把有规律的字符串切成列表从而方便取值

info='egon:18:180:150' res=info.split(':',1) print(res) print(res[1]) info='egon:18:180:150' res=info.split(':') print(res) s1=res[0]+':'+res[1]+':'+res[2]+':'+res[3] s1=''
for item in res: s1+=item print(s1) s1=':'.join(res) print(s1) ':'.join([1,2,3,4,5])

 

 

7.循环

for i in 'hello': print(i)

 

 

****须要掌握的操做

1.strip , lstrip , rstrip 

msg='*****hello****'
print(msg.strip('*')) print(msg.lstrip('*')) print(msg.rstrip('*'))

 

2.lower , upper

msg='AaBbCc123123123'
print(msg.lower()) print(msg.upper()) #执行以后 #aabbcc123123123 #AABBCC123123123

 

3. startswith , endswith

msg='alex is dsb'
print(msg.startswith('alex')) print(msg.endswith('sb')) #执行以后 #True #True

 

4.format 的三种玩法

msg='my name is %s my age is %s' %('egon',18) print(msg) #执行以后
#my name is egon my age is 18

msg='my name is {name} my age is {age}'.format(age=18,name='egon') print(msg) #执行以后 #my name is egon my age is 18

 

msg='my name is {} my age is {}'.format(18,'egon') msg='my name is {0}{0} my age is {1}{1}{1}'.format(18,'egon') print(msg) #执行以后 #my name is 1818 my age is egonegonegon

 

5.split , rsplit 

cmd='get|a.txt|33333'
print(cmd.split('|',1)) print(cmd.rsplit('|',1)) #执行以后 #['get', 'a.txt|33333'] #['get|a.txt', '33333']

 

6. replace 

msg='kevin is sb kevin kevin'
print(msg.replace('kevin','sb',2)) #sb is sb sb kevin

 

7. isdigit (当字符串内为纯数字时结果为True

res='11111'
print(res.isdigit()) int(res) #True

 

age_of_bk=18 inp_age=input('your age: ').strip() if inp_age.isdigit(): inp_age=int(inp_age) #int('asdfasdfadfasdf')
    if inp_age > 18: print('too big') elif inp_age < 18: print('to small') else: print('you got it') else: print('必须输入纯数字')

 

 

** (了解)

1.find, rfind, index, rindex, count

find 和 index用法差很少,find比index功能强大,优先使用find

print('xxxkevin is sb kevin'.find('kevin')) print('xxxkevin is sb kevin'.index('kevin')) print('xxxkevin is sb kevin'.rfind('kevin')) print('xxxkevin is sb kevin'.rindex('kevin')) #执行以后
3
3
15
15

 

print('kevin is kevin is kevin is sb'.count('kevin')) #执行以后 # 3

 

2. center, ljust ,rjust , zfill

print('egon'.center(50,'*')) print('egon'.ljust(50,'*')) print('egon'.rjust(50,'*')) print('egon'.zfill(50)) #执行以后
***********************egon*********************** egon**********************************************
**********************************************egon 0000000000000000000000000000000000000000000000egon

 3. captalize , swapcase , title

print('my name is kevin'.capitalize())　　#一句话的第一个字母大写 print('AaBbCc'.swapcase())　　　　#将大写字母变成小写,小写变大写 print('my name is kevin'.title())　　　　#每个单词的首字母大写 #执行以后
My name is kevin aAbBcC My Name Is Kevin

 

 

 

4.is其余

name='egon123'
print(name.isalnum()) #字符串由字母或数字组成
print(name.isalpha()) #字符串只由字母组成

print(name.islower()) print(name.isupper()) name='    '
print(name.isspace()) msg='I Am Egon'
print(msg.istitle()) #执行以后
True False True False True True