Python_ base Type

"Basic data types and literacy in Python" One, the binary 1. Introduction to the system

The binary system is a kind of carry-out method which is stipulated by people. Data operations and storage at the bottom of the computer are binary data. Computer language is binary, the computer can directly recognize the binary data, the other data can not be directly recognized.

2. Commonly used in the system　

For any one of the binary---x-binary, it means that the number operation at a certain position is every X-step. Decimal is every ten into a, hexadecimal is every 16 into a, binary is every two into one, and so on, X-System is every x carry. We often use binary, octal, decimal, hexadecimal.

• Decimal: There are 10 basic numbers, respectively 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, arithmetic rules "every ten into one";

• Octal: There are 8 basic numbers, respectively 0, 1, 2, 3, 4, 5, 6, 7, arithmetic rules "every eight into one"

• Hex: There are 16 basic numbers, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, and the operational rules "every 16 in one".

• Binary: There are 2 basic numbers, respectively, 0, 1, the operational rules "every two into one."

3. Binary conversion

We have the most common conversion method: Divide the decimal data by the target binary to get the remainder, and the remainder from the last to the first permutation, is the converted target binary representation ("in addition to the base of the remainder , until the quotient is 0, the remainder reversal "). Take the decimal 43-to-binary conversion example:

The resulting numerical arrangement: 101011, so the decimal 43 binary representation is 101011, the same way, if the octal, hexadecimal representation, 43 divided by 8, 16.

II. 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 print (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 print (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 p Rint (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}" 9 V3 = Tpl3.format (name= ' Li Jie ', age=19,gender= ' random ') print (v3) All Tpl4 = "I am: {nam e}; Ages: {Age}; Gender: {gender} "V4 = Tpl4.format_map ({' name ': ' Li Jie ', '": ' ", ' gender ': ' In '} ') print (v4)

Output:

I am: hexin; age: 18; Gender: Man I am: Li Jie; age: 19; Sex: All Right I am: Li Jie; age: 19; Sex: Casual I am: Li Jie; age: 19; Gender: Middle

• ) 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 print (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 (name_list) 8 pri NT (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 print (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 = 15v = 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, 11, 111] [111, 11, 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]pri NT (item) #1 eric#2 alex#3 tony# Please enter the product serial number: 1#eric

6.tuple tuples

Cannot be modified type, tuple element cannot be modified, Ganso is other type data can be modified

• 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 tuple elements are other types that can be modified

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 '}

Python_ base Type