Python database 5.json, hashlib, base64 module

5.1 json

JS objects

teacher_1 = {var 
    name: 'juhao', 
    Age: 18 is,  Feature: [ 'high', 'rich', 'handsome'] }
 

JSON string

{ 
    "Name": "juhao", 
    "Age": 18 is, 
 "Feature": [ 'high', 'rich', 'handsome'] }

Python dictionary

{ 
    'Name': 'juhao', 
    'Age': 18 is  'Feature': [ 'high', 'rich', 'handsome'] }
 

note

1. The string must be enclosed in double quotes (ie: "") to include the 2 may be a string, numeric, true, false, null, list, or dictionary.

• 1. The python data into json:

  json.dumps (obj) Indent indent achieved (typically. 4), json.dumps (obj, indent =. 4) ensure_ascii ascii whether to use analytical ensure_ascii = False

• 2. python json data into data:

  2.json.loads(s)

• 3. converted to json and saved to a file

  3.json.dump(obj, fp)

• 4. JSON read from a file, and data into python

  4.json.load(fp)

---

with open ('json_test','w+')as f:
    json.dump(obj,indent = 4,ensure_ascii = False,fp=f)

with open ('json_test','r+')as f:
    res = json.load(fp=f)
    print res

5.2 hashlib, base64 module

1.hashlib （MD5）

hash algorithm is - the kind of data of arbitrary length into a fixed-length function data

• 1. Symmetric encryption:

  Data encryption and decryption using the same key

• 2. Asymmetric encryption:

  Encryption and decryption using two different keys, a public key used to encrypt the data, the private key is used to decrypt the data

• 3-way encryption:

  Only encrypt data, not decrypt the data

2.Hash structure:

Irreversible: Unable to restore the original data from the hash value of the fixed-length output: No matter how long the original data input, the result is the same length anti-modifying properties: small changes in input, even if only one character will cause results major changes and strong impact resistance: the same hash value is difficult to find two different data content, so that they have the almost impossible

Hashlib module provides a number of hash algorithms are:

1.Md5 
2.SHA series: sha1, sha224, sha256, sha384 , sha512

api description:

hashlib.new (name, data = b " )   to generate a hash objects 
hashlib.hash algorithm name (data = b")  to generate a target using the hash algorithm 
Hash object .update (arg = None) to update the object hash 
Hash object .digest () return value (bytes type) obtained Hash algorithm Hash object .hexdigest () return value (str type) Hash algorithm obtained

​
    import hashlib
 
 result = hashlib.new('md5','南北'.encode())
 
 result = hashlib.md5('南北'.encode())
 
 print(result.digest（）)
 print(result.hexdigest（）)
 
 result = hashlib.md5()
 result.update('南北'.encode())
 
 print(result.digest（）)
 print(result.hexdigest（）)
​

3.base64

64 is a base64 characters with a method of representing arbitrary binary data (binary data encoded into ASCII characters) using AZ, az, 0-9, +, / 64 characters which

Features:

Used to convert the data into a non-ASCII characters in the ASCII character is a method used to encode the URL of the binary data can be converted to non-printed printable string

 

api description:

base64.b64encode (s) of the binary data base64 encoding 
base64.b64decode (s) decodes the encoded data by base64 base64.urlsafe_b64encode (s) a URL base64 encoding base64.urlsafe_b64decode (s) decodes

---

import base64
​
data = '爱我'
res = base64.b64encode(data.encode)

---

​
    
 
 import json
 import base64
 
 data={
    'name':'nanbei',
    'age':10,
    'feature':["gao","fu","shuai"]
 }
 
 with open('my_json,txt','w')as f:
    json.dump(data,f,ensure_ascii=False)
 
 with open('my_json,txt','r')as f:
    result=json.load(f)
    print(type(result))
    print(result['feature'][2])
 
 with open('my_json,txt','rb')as f:
    result=base64.b64encode(f.read())
 
 with open('my_json,txt','wb')as f:
    f.write(result)
 
 with open('my_json,txt','rb')as f:
    print(base64.b64decode(f.read()).decode())
​
​