Python full stack development "second piece" Python data type

numeric types and String types

The 1.bin () function converts decimal into a binary

The 2.OCT () function converts decimal into octal

The 3.hex () function converts decimal into hexadecimal

Hexadecimal representation: 0-9 a B c d E F

4. Characteristics of numeric types:

Only one value can be stored

Once defined, cannot be changed

Direct access

Categories: integers, booleans, floating-point, plural

5. String type

Quotation marks contain string types

s1= ' Hello world ' s= "Hello World"

s2= "" "Hello World" ""

s3= ' Hello World '

Single-lead double-lead no difference

6. Common Operations for strings

Strip () remove whitespace, or remove other characters

Slipt () split, separated by a space by default. can also be split with other characters

Len () Length slice: such as print (X[1:3]) is also Gu Tou regardless of the tail

Print (X[0:5:2]) #0 2 4

Capitalize () Capitalize first letter

Center () Center Display for example: x= ' Hello ' Print (X.center (30, ' # '))

Count (): Count, Gu Tou regardless of the tail, count the number of characters, the space is also counted as a character

EndsWith () at what end

Satrtswith () Start with what

Find () finds the index position of the character, if it is negative, indicates that the lookup failed

Index () indexes

The difference between find () and index (), such as:

　　　　　　

Format () string formatting

1.msg= ' name:{},age:{},sex:{} '

Print (Msg.format (' Haiyan ', 18, female))

2.msg= ' name:{0},age:{1},sex:{0} '

Print (Msg.format (' aaaaaa ', ' bbbbbb '))

3.msg= ' Name:{x},age:{y,sex:{z} '

Print (Msg.format (x= ' Haiyan ', y= ', z= ' women '))

IsDigit () Determine if it is a number

Islower () to determine whether it is all lowercase

Isupper () to determine if it is all uppercase

Lower () convert all to lowercase

Upper () Convert all to uppercase

Isspace () Determine if it is all spaces

Istitle () to determine if it is a title (capitalized in the first letter)

Swapcase () uppercase and lowercase letters flipped

Join () connection

Repalce () Replace

msg= ' Hello Alex '

Print (Msg.replace (' e '), ' A ', 1)

Print (Msg.replace (' e '), ' A ', 2)

Ljust () Align Left

x= ' ABC ' Print (X.ljust (10, ' * '))

Some methods of string formatting and string

1.%s,%d

Example 1:name= ' Egon '

Age=20

Print ("My name is%s my age is%s"% (name,age)) #%s can accept both a string and a number

Print (' My name is%s my age is%d '% (name,age)) #%d can only accept numbers

Example 2: Display of user information

1 while True:2     name=input ("Name:") 3     Age=input ("Age:") 4     sex=input ("Sex:") 5     height=input ("Height:") ) 6     msg= "7              ------------%s Info-----------8              name:%s 9              age:%s10              sex:%s11              height:%s12              ------------------------------         "% (name,name,age,sex,heigth)     print (msg)

The results of the operation are as follows:

2. String methods

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465 6667686970717273747576777879808182838485868788899091929394959697989910010110210310410510610710810911011111211311411511611 7118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157 1581591601611621631641651661671681691701711721731741751761771781791801811821831841851861871881891901911921931941951961971 98199200201202203204205

# name=‘egon‘ #name=str(‘egon‘)# print(type(name)) #优先掌握#1.移除空白strip# msg=‘             hello         ‘# print(msg)# print(msg.strip())# 移除‘*’# msg=‘***hello*********‘# msg=msg.strip(‘*‘)# print(msg)#移除左边的# print(msg.lstrip(‘*‘))#移除右边的# print(msg.rstrip(‘*‘)) #用处whileTrue:    name=input(‘user: ‘).strip()    password=input(‘password: ‘).strip()    ifname ==‘egon‘andpassword ==‘123‘:        print(‘login successfull‘)#切分split# info=‘root:x:0:0::/root:/bin/bash‘# print(info[0]+info[1]+info[2]+info[3])# user_l=info.split(‘:‘)# print(user_l[0])# msg=‘hello world egon say hahah‘# print(msg.split()) #默认以空格作为分隔符#cmd=‘download|xhp.mov|3000‘# cmd_l=cmd.split(‘|‘)# print(cmd_l[1])# print(cmd_l[0])# print(cmd.split(‘|‘,1))#用处whileTrue:    cmd=input(‘>>:　‘).strip()    if len(cmd) ==0:continue    cmd_l=cmd.split()    print(‘命令是:%s 命令的参数是:%s‘%(cmd_l[0],cmd_l[1]))#长度len# print(len(‘hell 123‘))#索引# 切片:切出子字符串# msg=‘hello world‘# print(msg[1:3]) #1 2# print(msg[1:4]) #1 2 3# 掌握部分oldboy_age=84whileTrue:    age=input(‘>>: ‘).strip()    iflen(age) ==0:        continue    ifage.isdigit():        age=int(age)    else:        print(‘must be int‘)#startswith,endswith# name=‘alex_SB‘# print(name.endswith(‘SB‘))# print(name.startswith(‘alex‘))#replace# name=‘alex say :i have one tesla,my name is alex‘# print(name.replace(‘alex‘,‘SB‘,1))# print(‘my name is %s my age is %s my sex is %s‘ %(‘egon‘,18,‘male‘))# print(‘my name is {} my age is {} my sex is {}‘.format(‘egon‘,18,‘male‘))# print(‘my name is {0} my age is {1} my sex is {0}:{2}‘.format(‘egon‘,18,‘male‘))# print(‘my name is {name} my age is {age} my sex is {sex}‘.format(#     sex=‘male‘,#     age=18,#     name=‘egon‘)) # name=‘goee say hello‘# # print(name.find(‘S‘,1,3)) #顾头不顾尾,找不到则返回-1不会报错,找到了则显示索引# # print(name.index(‘S‘)) #同上,但是找不到会报错## print(name.count(‘S‘,1,5)) #顾头不顾尾,如果不指定范围则查找所有#join# info=‘root:x:0:0::/root:/bin/bash‘# print(info.split(‘:‘))# l=[‘root‘, ‘x‘, ‘0‘, ‘0‘, ‘‘, ‘/root‘, ‘/bin/bash‘]# print(‘:‘.join(l))#lower,upper# name=‘eGon‘# print(name.lower())# print(name.upper())#了解部分#expandtabs# name=‘egon\thello‘# print(name)# print(name.expandtabs(1))#center,ljust,rjust,zfill# name=‘egon‘# # print(name.center(30,‘-‘))# print(name.ljust(30,‘*‘))# print(name.rjust(30,‘*‘))# print(name.zfill(50)) #用0填充#captalize,swapcase,title# name=‘eGon‘# print(name.capitalize()) #首字母大写,其余部分小写# print(name.swapcase()) #大小写翻转# msg=‘egon say hi‘# print(msg.title()) #每个单词的首字母大写#在python3中num0=‘4‘num1=b‘4‘#bytesnum2=u‘4‘#unicode,python3中无需加u就是unicodenum3=‘四‘#中文数字num4=‘Ⅳ‘#罗马数字#isdigt:str,bytes,unicode# print(num0.isdigit())# print(num1.isdigit())# print(num2.isdigit())# print(num3.isdigit())# print(num4.isdigit())#isdecimal:str,unicode# num0=‘4‘# num1=b‘4‘ #bytes# num2=u‘4‘ #unicode,python3中无需加u就是unicode# num3=‘四‘ #中文数字# num4=‘Ⅳ‘ #罗马数字# print(num0.isdecimal())# # print(num1.)# print(num2.isdecimal())# print(num3.isdecimal())# print(num4.isdecimal())#isnumeric:str,unicode,中文，罗马# num0=‘4‘# num1=b‘4‘ #bytes# num2=u‘4‘ #unicode,python3中无需加u就是unicode# num3=‘四‘ #中文数字# num4=‘Ⅳ‘ #罗马数字## print(num0.isnumeric())# # print(num1)# print(num2.isnumeric())# print(num3.isnumeric())# print(num4.isnumeric())#is其他# name=‘egon123‘# print(name.isalnum()) #字符串由字母和数字组成# name=‘asdfasdfa sdf‘# print(name.isalpha()) #字符串只由字母组成## name=‘asdfor123‘# print(name.isidentifier())name=‘egGon‘print(name.islower())# print(name.isupper())# print(name.isspace())name=‘Egon say‘print(name.istitle())

　　

Python full stack development "second piece" Python data type