"Basic operations of basic data types for Python"

I. Basic data type 1. String

Class: Str

Method: Select str, hold command (CTRL) + Left button to jump to the corresponding method

The usual methods of string are summarized as follows:

• 1) Capitalize

Function: Implement the first letter of the string, not change itself, will generate a new value

Capitalize

Example:

1 #!/usr/bin/env python2 #-*-coding:utf-8-*-3 name = ' Hexin ' 4 v = name.capitalize () #调用str类, execute the method where capitalize is 5 prin T (v)

Output:

Hexinhexin

• 2) Casefold

Function: Turn all uppercase letters into lowercase, and support multiple language changes in addition

Casefold

Example:

1 name = ' Hexin ' 2 v = name.casefold () 3 print(name) 4 print (v) 

Output:

Hexinhexin

• 3) Lower,upper

Function:

Lower: lowercase all caps, limited English

Upper: Capitalize all lowercase

Lower

Example:

1 name = ' Hexin ' 2 v = name.lower () 3 print(name) 4 print (v) 

Results:

Hexinhexin

• 4) Center

Function: text centered, padding character in white space

Parameter 1: Total length, Parameter 2: space-filled characters (length 1)

Center

Example:

1 name = ' Hexin ' 2 v = name.center (' * ') 3 print(name) 4 print (v) 

Output:

hexin*******hexin********

• 5) Count

Function: Indicates the number of occurrences of a subsequence to find in a string

Parameter 1: The value to find (sub-sequence), Parameter 2: Start position (index), parameter 3: End position (index)

Count

Example:

1 name = ' HEXINDDAKLFJSL;DFJCNLJDAJSFLAJDF ' 2 v = name.count (' A ') 3 i = Name.count (' A ', 0,15) 4 print(name) 5 Prin T(v) 6 print (i)   

Output:

31

• 6) EndsWith

Function: Judge whether to end with XX

Parameter 1: Judging value, Parameter 2, 3: Position of start and end (number)

EndsWith

Example:

1 name = ' HEXINDDAKLFJSL;DFJCNLJDAJSFLAJDF ' 2 v = name.endswith (' df ') 3 i = Name.endswith (' n ', 0,5) 4 print(name ) 5 Print(v) 6 print (i)   

Output:

Hexinddaklfjsl;dfjcnljdajsflajdftruetrue

• 7) Expandtabs

function: Find tab \ t, replace (with previous value)

Expandtabs

Example:

1 name = "AL\TE\TX\NALEX\TUU\TKKK" 2 v = name.expandtabs (5)  #包含前面的值, 5 length 3 print (v)

Output:

Al   e    xalex uu   KKK

• 8) Find

Function: Find the index position of the specified subsequence, there is no return-1

Find

Example:

1 name = ' Hexin ' 2 v = name.find (' 0 ') 3 i = Name.find (' x ') 4 print(v) 5 print (i)  

Output:

-12

• 9) Format,%s,format_map

Function: String formatting

format

Format_map

Example:

1 TPL1 = "I am:%s; age:%s; Gender:%s"% ( ' Hexin ', ' m ', ' Man ') 2 print(TPL1) 3  4 tpl2 = "I am: {0}; Age: {1}; Gender: {2}" 5 v2 = Tpl2.format ("Li Jie", 19, ' All Lines ') 6 print (v2) 7  8 tpl3 = "I am: {name}; Age: {}; Gender: {Gender}" 9 V3 = Tpl3.format (name= ' Li Jie ', age=19,gender= ' casual ') 10 Print(v3) one page tpl4 = "I am: {name}; Age: {Gender}; Gender: {"} "V4 = Tpl4.format_map ({' name ': ' Li Jie ', ' ages ': +, ' gender ': ' in ') }) Print (v4)      

Output:

I am: hexin; age:; Gender: Man I am: Li Jie; age: N; Gender: All Right I am: Li Jie; age: N; Gender: Casual I am: Li Jie; age: 19; Gender:  

• ) isalnum

Function: Whether it is a number or a Chinese character

isalnum

Example:

1 name = ' Hexin0 good ' 2 v = name.isalnum () 3 print (v)

Output:

True

• One) isdecimal,isdigit,isnumeric

Function: Whether it is a number

isalnumIsdecimalIsDigit

Example:

1 num = ' two ' 2 V1 = num.isdecimal () # ' 123 ' 3 v2 = Num.isdigit ()   # ' 123 ', ' ② ' 4 v3 = num.isnumeric () # ' 123 ', ' two ', ' ② ' 5 prin T (V1,V2,V3)

Output:

False False True

• Isidentifer)

Function: Whether it is a valid identifier

Isidentifier

Example:

1 n = ' 1name ' 2 u = ' name ' 3 v = n.isidentifier () 4 i = u.isidentifier () 5 print(v) 6 print (i)  

Output:

Falsetrue

• Islower (Isupper)

function: all lowercase (uppercase)

Islower

Example:

1 name = ' Hexin ' 2 name1 = ' hexin ' 3 v = name.islower () 4 i = name1.islower () 5 print(v) 6 print (i)

Output:

TrueFalse

• isprintable)

Function: Contains implied XX (False for invisible characters including \n,\t)

isprintable

Example:

1 name = ' Hexindas\talj,hexin ' 2 v = name.isprintable () 3 print (v)

Output:

False

• ) Join

Function: Element stitching

Join

Example:

1 name = ' Hexin ' 2 3 v = ' _ '. Join (name) # inner loop each element 4 print(v) 5 6 name_list = [' 1 ', ' 2 ', ' 3 ', ' 4 ']7 v = "+". Join (Nam E_list) 8 Print (v)  

Output:

H_e_x_i_n1+2+3+4

• Rjust,ljust)

Function: Fill left and right, like center

Ljust

Example:

1 name = ' Hexin ' 2 v = name.ljust (+, ' * ') 3 i = Name.rjust (6, ' * ') 4 print(v) 5 print (i)  

Output

Hexin**********hexin

• Maketrans,translate)

Function: Create correspondence, translate transformations

Maketrans

Example:

1 m = Str.maketrans (' Aeiou ', ' 12345 ') # correspondence 2 name = "AKPSOJFASDUFASDLKFJ8AUSDFAKJSDFL;KJER09ASDF" 3 v = name.translate (m) 4 print (v)

Output:

1kps4jf1sd5f1sdlkfj815sdf1kjsdfl;kj2r091sdf

• ) partition

Function: Split, preserve split elements

Partition

Example:

1 content = "9sb6sb6" 2 v = content.partition (' SB ') # Partition3 print (v)

Output:

(' 9 ', ' SB ', ' 6sb6 ')

• +) Replace

function: Replace

Replace

Example:

1 content = "1SB2SB3SB4" 2 v = content.replace (' sb ', ' Love ') 3 print(v) 4 v = content.replace (' sb ', ' Love ', 1) 5 pri NT (v)  

Output:

1love2love3love41love2sb3sb4

• Strip)

Features: Remove whitespace, \n,\t, custom

Strip

Example:

1 name = ' hexin \ t ' 2 v = name.strip () # blank, \n,\t3 print (v)

Output:

Hexin

• ) Zfill

Function: Fill 0

Zfill

Example:

1 name = ' Hexin ' 2 v = Name.zfill (3) print (v)

Output:

000000000000000hexin

2. Integer

class int

• 1) bit_length

Function: The minimum number of digits for the binary representation of the current integer

Bit_length

Example:

Age = 4 # 100print (Age.bit_length ())

Output:

3

• 2) To_bytes

Function: Gets the byte representation of the current data

to_bytes

Example:

Age = Allv = age.to_bytes (10,byteorder= ' big ') v = age.to_bytes (10,byteorder= ' little ') print (v)  

Output:

B ' \x0f\x00\x00\x00\x00\x00\x00\x00\x00\x00 '

3.list List

Class List

Variable type

• 1) Append

Function: Append

Append

Example:

User_list = [' Tom ', ' Liu ', ' Jack ', ' n '] # variable type user_list.append (' hex ') print (user_list)

Output

[' Tom ', ' Liu ', ' Jack ', ' n ', ' hex ']

• 2) Clear

Function: Empty

Example:

User_list = [' Tom ', ' Liu ', ' Jack ', ' n '] # variable type user_list.clear () print (user_list)

Output:

[]

• 3) Copy

function: Shallow copy

Example:

User_list = [' Tom ', ' Liu ', ' Jack ', ' n '] t = user_list.copy () print(user_list) print (t)  

Output:

[' Tom ', ' Liu ', ' Jack ', ' n '[' Tom ', ' Liu ', ' Jack ', ' n ']

• 4) Count

Function: Count

Example:

User_list = [' Tom ', ' N ', ' Liu ', ' Jack ', ' n ', ' n ']t = User_list.count (' n ') print (user_list) print (t)  

Output:

[' Tom ', ' N ', ' Liu ', ' Jack ', ' n ', ' n ']3

• 5) Extend

Features: Extending the original list

Example:

User_list = [' Tom ', ' N ', ' Liu ', ' Jack ', ' n ', ' n ']user_list.extend (' 9 ') print (user_list) 

Output:

[' Tom ', ' N ', ' Liu ', ' Jack ', ' n ', ' n ', ' 9 ']

• 6) Index

Function: Find element index, no error

Example:

User_list = [' Tom ', ' N ', ' Liu ', ' Jack ', ' n ', ' n ']v = User_list.index (' n ') print (v) 

Output:

1

• 7) Pop

Function: Delete and get elements, index

Example:

User_list = [' Tom ', ' N ', ' Liu ', ' Jack ', ' n ', ' n ']v = user_list.pop (1) print (v) print (user_list)  

Output:

n[' Tom ', ' Liu ', ' Jack ', ' n ', ' n '

• 8) Remove

Function: Delete, value

Example:

User_list = [' Tom ', ' N ', ' Liu ', ' Jack ', ' n ', ' n ']user_list.remove (' n ') print (user_list) 

Output:

[' Tom ', ' Liu ', ' Jack ', ' n ', ' n ']

• 9) Reverse

Function: Flip

Example:

User_list = [' Tom ', ' N ', ' Liu ', ' Jack ', ' n ', ' n ']user_list.reverse () print (user_list)

Output:

[' n ', ' n ', ' Jack ', ' Liu ', ' N ', ' Tom ']

• ) sort

Function: Sort

Example:

num = [11,2,3,6,111]num.sort () print(num) num.sort (reverse=True) print (num)  

Output:

[2, 3, 6, one, 111][111, one, 6, 3, 2]

4.range

• 1) Create

py2.7: Generate numbers now

Range (1,11) # Generate 1,23,,4,56.10

Py3: Will not be generated immediately, only the loop iteration, only one generation;

For I in range (1,11):     print(i) for J in range (1,11,2):     print(j) for K in range (10,0,-1):     Print (k)    

123456789101357910987654321

Example

# li = [' Eric ', ' Alex ', ' Tony ']
# for I in range (0,len (LI)):
#     ele = li[i]
#     Print (ele)


Li = [' Eric ', ' Alex ', ' Tony ']
For I in Li:
    Print (i)

# for I in range (0,len (LI)):
#     print (I+1,li[i])

Output

Ericalextony

5.enumerate

Function: Generate an extra column of sequential numbers

Example

Li = [' Eric ', ' Alex ', ' Tony ']for I,ele in Enumerate (li,1):    print(i,ele) #1 eric#2 alex#3 Tony
     

Li = [' Eric ', ' Alex ', ' Tony ']for I,ele in Enumerate (li,1):    print(i,ele) v = input (' Please enter product serial number: ') v =  Int (v) item = Li[v-1]print(item) #1 eric#2 alex#3 tony# Please enter the product serial number: 1#eric      

6.tuple tuples

Cannot be modified, son cannot be modified, grandson can

• 1) Create

User_tuple = (' Hex ', ' Eric ', ' Seven ', ' Hex ')

• 2) Count

Function: Get the number

User_tuple = (' Hex ', ' Eric ', ' Seven ', ' Hex ') v = user_tuple.count (' hex ') print (v)

#2

• 3) Index

Function: Get the first index position worth

User_tuple = (' Hex ', ' Eric ', ' Seven ', ' Hex ') v = user_tuple.index (' hex ') print(v) #0  

• 4) Note: Tuple last comma

Example

Li = (' hx ',) print (LI)

• 5) cannot be modified by itself, but grandson can

User_tuple = (' Alex ', ' Eric ', ' Seven ', [' 1 ', ' 2 ', ' 3 '], ' A4 ')
# User_tuple[0] = 123 execution Error
# User_tuple[3] = [11,22,33] Execution error
USER_TUPLE[3][1] = ' 0 '
Print (User_tuple)

7.dict

Variable type

• 1) Clear

Function: Empty

DiC = {' K1 ': ' v1 ', ' K2 ': ' V2 '}dic.clear () print (DIC)

• 2) Copy

function: Shallow copy

DiC = {' K1 ': ' v1 ', ' K2 ': ' v2 '}v = dic.copy () print (v) 

• 3) Get

Function: Gets the specified value according to key, no error is present

DiC = {' K1 ': ' v1 ', ' K2 ': ' v2 '}v = dic.get (' k1111 ', 1111) print (v) 

• 4) Pop

Function: Delete and get the corresponding value values

# dic = {' K1 ': ' v1 ', ' K2 ': ' v2 '}# v = dic.pop (' k1 ') # print (DIC) # print (v)

Output:

{' K2 ': ' v2 '}v1

• 5) Popitem

function: Random Delete key value pair, and get to delete key value

DiC = {' K1 ': ' v1 ', ' K2 ': ' v2 '}v = dic.popitem () print(DIC) print (v)  

Output:

{' K1 ': ' V1 '} (' K2 ', ' v2 ')

DiC = {' K1 ': ' v1 ', ' K2 ': ' v2 '}k,v = Dic.popitem () # (' K2 ', ' v2 ') print(DIC) print (k,v) 

Output:

{' K2 ': ' v2 '}K1 v1

DiC = {' K1 ': ' v1 ', ' K2 ': ' v2 '}v = Dic.popitem () # (' K2 ', ' v2 ') print(DIC) print (v[0],v[1]) 

Output:

{' K1 ': ' v1 '}K2 v2

• 6) SetDefault

Function: Add, delete if not present

DiC = {' K1 ': ' v1 ', ' K2 ': ' V2 '}dic.setdefault (' K3 ', ' v3 ') print(DIC) dic.setdefault (' K1 ', ' 1111111 ') Print (DIC)   

Output:

{' K2 ': ' v2 ', ' K1 ': ' v1 ', ' K3 ': ' V3 '} {' K2 ': ' v2 ', ' K1 ': ' v1 ', ' K3 ': ' V3 '}

• 7) Update

Features: Batch additions or modifications

DiC = {' K1 ': ' v1 ', ' K2 ': ' V2 '}dic.update ({' K3 ': ' V3 ', ' K1 ': ' V24 '}) print (DIC) 

Output:

{' K1 ': ' v24 ', ' K2 ': ' v2 ', ' K3 ': ' V3 '}

• 8) Fromkeys

Function: Creates a new dictionary from the sequence key and value set to value.

Example:

DIC = Dict.fromkeys ([' K1 ', ' K2 ', ' K3 '],123) dic[' k1 '] = ' asdfjasldkf ' Print (DIC)

Output:

{' K2 ': 123, ' K1 ': ' asdfjasldkf ', ' K3 ': 123}

8.set

collection, non-repeating list, mutable type.

• 1) Create

S1 = {"Alex", ' Eric ', ' Tony '}print(Type (S1)) print (S1) 

Output:

<class ' Set ' >{' Alex ', ' Eric ', ' Tony '}

• 2) Difference

Function: Presence in output S1, value not present in S2

S1 = {"Alex", ' Eric ', ' Tony ', ' II '}s2 = {"Alex", ' Eric ', ' Tony ', ' hexin '}v = s1.difference (s2) print (v) 

Output:

{' II '}

• 3) Difference_update

Function: exists in S1, S2 does not exist, then S1 is emptied and then re-assigned

S1 = {"Alex", ' Eric ', ' Tony ', ' II '}s2 = {"Alex", ' Eric ', ' Tony ', ' Hexin '}s1.difference_update (S2) print (S1) 

Output:

{' II '}

• 4) Symmetric_difference

Function: exists in S1, value not present in S2 and S2, value not present in S1

S1 = {"Alex", ' Eric ', ' Tony ', ' II '}s2 = {"Alex", ' Eric ', ' Tony ', ' hexin '}v = s1.symmetric_difference (s2) print ( V)  

{' II ', ' hexin '}

• 5) Intersection

Function: Intersection

S1 = {"Alex", ' Eric ', ' Tony ', ' II '}s2 = {"Alex", ' Eric ', ' Tony ', ' hexin '}v = s1.intersection (s2) print (v) 

Output:

{' Eric ', ' Alex ', ' Tony '}

• 6) Union

Features: and set

S1 = {"Alex", ' Eric ', ' Tony ', ' II '}s2 = {"Alex", ' Eric ', ' Tony ', ' hexin '}v = s1.union (s2) print (v)  

Output:

{' Alex ', ' Hexin ', ' Eric ', ' II ', ' Tony '}

• 7) Discard

Function: Remove

S1 = {"Alex", ' Eric ', ' Tony ', ' II '}s2 = {"Alex", ' Eric ', ' Tony ', ' Hexin '}s1.discard (' Alex ') print (S1) 

Output:

{' Eric ', ' Tony ', ' II '}

• 8) Update

Features: Adding

S1 = {"Alex", ' Eric ', ' Tony ', ' Li Quan ', ' Li Quan '}s1.update ({' Alex ', ' 123123 ', ' FFF '}) print (S1) 

Output:

{' FFF ', ' Li Quan ', ' 123123 ', ' Tony ', ' Alex ', ' Eric ', ' Li Quan 11 '}

9. Boolean Values

• Create

A = Trueb = Flase

• Transformation

The number conversion only 0 is flase, the string only "" is Flasev = bool () print (v) Two, the basic operation 1. Arithmetic operations:

Note: The order in which operators are executed, from the previous

2. Comparison operation:

3. Assignment operation:

4. Logic operation:

5. Member Operations:

"Basic operations of basic data types for Python"