Python数据库 5.json,hashlib,base64模块

JS对象

<span>var teacher_1 = {<br><span>    name: ‘juhao’,<br><span>    age: 18,<br><span> <span class="cm-tab">   feature : [‘高’, ‘富’,  ‘帅’]<br><span>}</span></span></span></span></span></span>

JSON字符串

<span>{<br><span>    “name”: “juhao”,<br><span>    “age”: 18,<br><span><span class="cm-tab">    “ feature “ : [‘高’, ‘富’,  ‘帅’]<br><span><span>?<br><span>}</span></span></span></span></span></span></span></span>

Python字典

<span>{<br><span>    ‘name’: ‘juhao’,<br><span>    ‘age’: 18<br><span> <span class="cm-tab">   ‘feature’ : [‘高’, ‘富’,  ‘帅’]<br><span><span>?<br><span>}</span></span></span></span></span></span></span></span>

注意

<span>1.字符串必须用双引号（即：””）来包括<br><span><span>?<br><span>2.值可以是字符串、数字、true、false、null、列表，或字典。</span></span></span></span>

• 1.将python数据转化为json:

  json.dumps(obj) Indent实现缩进(一般是4)， json.dumps(obj，indent = 4) ensure_ascii 是否用ascii解析 ensure_ascii = False

• 2.将json数据转换为python的数据:

  2.json.loads(s)

• 3.转换为json并保存到文件中

  3.json.dump(obj, fp)

• 4.从文件中读取json，并转化为python数据

  4.json.load(fp)

<span>with open (‘json_test‘,‘w+‘)as f:<br><span><span class="cm-tab">    json.dump(obj,indent = 4,ensure_ascii = False,fp=f)</span></span></span>

<span>with open (‘json_test‘,‘r+‘)as f:<br><span><span class="cm-tab">    res = json.load(fp=f)<br><span><span class="cm-tab">    print res</span></span></span></span></span>

5.2 hashlib,base64模块

1.hashlib （MD5）

hash算法就是-种将任意长度的数据变成一个长度固定的数据的函数

• 1.对称加密：

  数据加密解密使用相同的密钥

• 2.非对称加密：

  加密和解密用两把不同的密钥， 公钥用于加密数据，私钥用于解密数据

• 3.单向加密：

  只能加密数据，而不能解密数据

2.Hash结构：

<span>不可逆：无法根据散列值来还原原来的数据<br><span><span>?<br><span>定长输出：无论输入的原始数据有多长，结果长度是相同的<br><span><span>?<br><span>抗修改性：输入的微小改变，哪怕只有一个字符，会引起结果的巨大改变<br><span><span>?<br><span>强碰撞性：很难找到两段内容不同的数据，使他们产生的hash值一致，几乎不可能</span></span></span></span></span></span></span></span></span></span>

Hashlib模块提供了许多hash算法,主要有：

<span>1.md5<br><span>2.SHA系列：sha1, sha224, sha256, sha384, sha512</span></span>

api 描述：

<span>hashlib.new(name, data=b”)<span class="cm-tab">  生成一个hash对象<br><span>hashlib.hash算法名(data=b”)<span class="cm-tab">    生成一个使用该算法的hash对象<br><span>Hash对象.update(arg=None)<span class="cm-tab"> 更新hash对象<br><span>Hash对象.digest()<span class="cm-tab"> 返回Hash算法计算得到的值(bytes类型)<br><span><span>?<br><span>Hash对象.hexdigest()<span class="cm-tab">  返回Hash算法计算得到的值(str类型) </span></span></span></span></span></span></span></span></span></span></span></span>

<span><span>?<br><span><span class="cm-tab">    <span class="cm-keyword">import <span class="cm-variable">hashlib<br><span class="cm-tab-wrap-hack"><span class="cm-tab">    <br><span><span class="cm-tab">    <span class="cm-variable">result = <span class="cm-variable">hashlib.<span class="cm-property">new(<span class="cm-string">‘md5‘,<span class="cm-string">‘南北‘.<span class="cm-property">encode())<br><span class="cm-tab-wrap-hack"><span class="cm-tab">    <br><span><span class="cm-tab">    <span class="cm-variable">result = <span class="cm-variable">hashlib.<span class="cm-property">md5(<span class="cm-string">‘南北‘.<span class="cm-property">encode())<br><span class="cm-tab-wrap-hack"><span class="cm-tab">    <br><span><span class="cm-tab">    <span class="cm-builtin">print(<span class="cm-variable">result.<span class="cm-property">digest（）)<br><span><span class="cm-tab">    <span class="cm-builtin">print(<span class="cm-variable">result.<span class="cm-property">hexdigest（）)<br><span class="cm-tab-wrap-hack"><span class="cm-tab">    <br><span><span class="cm-tab">    <span class="cm-variable">result = <span class="cm-variable">hashlib.<span class="cm-property">md5()<br><span><span class="cm-tab">    <span class="cm-variable">result.<span class="cm-property">update(<span class="cm-string">‘南北‘.<span class="cm-property">encode())<br><span class="cm-tab-wrap-hack"><span class="cm-tab">    <br><span><span class="cm-tab">    <span class="cm-builtin">print(<span class="cm-variable">result.<span class="cm-property">digest（）)<br><span><span class="cm-tab">    <span class="cm-builtin">print(<span class="cm-variable">result.<span class="cm-property">hexdigest（）)<br><span><span>?</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

3.base64

base64是一种用64个字符来表示任意二 进制数据的方法， (将二 进制数据编码成ASCII字符)使用了A-Z,a-z,0-9,+ ,/这64个字符

特点:

<span>用来将非ASCII字符的数据转换成ASCII字符的一种方法<br><span><span>?<br><span>常用于对URL的编码<br><span><span>?<br><span>可以将不可打印的二进制数据转化为可打印的字符串</span></span></span></span></span></span></span>

api 描述:

<span>base64.b64encode(s)<span class="cm-tab"> 对二进制数据进行base64编码<br><span>base64.b64decode(s)<span class="cm-tab"> 对通过base64编码的数据进行解码<br><span><span>?<br><span>base64.urlsafe_b64encode(s)<span class="cm-tab"> 对URL进行base64编码<br><span>base64.urlsafe_b64decode(s)<span class="cm-tab">  解码</span></span></span></span></span></span></span></span></span></span>

<span>import base64<br><span><span>?<br><span>data = ‘爱我‘<br><span>res = base64.b64encode(data.encode)</span></span></span></span></span>

<span><span>?<br><span class="cm-tab-wrap-hack"><span class="cm-tab">    <br><span class="cm-tab-wrap-hack"><span class="cm-tab">    <br><span><span class="cm-tab">    <span class="cm-keyword">import <span class="cm-variable">json<br><span><span class="cm-tab">    <span class="cm-keyword">import <span class="cm-variable">base64<br><span class="cm-tab-wrap-hack"><span class="cm-tab">    <br><span><span class="cm-tab">    <span class="cm-variable">data={<br><span><span class="cm-tab">        <span class="cm-string">‘name‘:<span class="cm-string">‘nanbei‘,<br><span><span class="cm-tab">        <span class="cm-string">‘age‘:<span class="cm-number">10,<br><span><span class="cm-tab">        <span class="cm-string">‘feature‘:[<span class="cm-string">"gao",<span class="cm-string">"fu",<span class="cm-string">"shuai"]<br><span><span class="cm-tab">    }<br><span class="cm-tab-wrap-hack"><span class="cm-tab">    <br><span><span class="cm-tab">    <span class="cm-keyword">with <span class="cm-builtin">open(<span class="cm-string">‘my_json,txt‘,<span class="cm-string">‘w‘)<span class="cm-keyword">as <span class="cm-variable">f:<br><span><span class="cm-tab">        <span class="cm-variable">json.<span class="cm-property">dump(<span class="cm-variable">data,<span class="cm-variable">f,<span class="cm-variable">ensure_ascii=<span class="cm-keyword">False)<br><span class="cm-tab-wrap-hack"><span class="cm-tab">    <br><span><span class="cm-tab">    <span class="cm-keyword">with <span class="cm-builtin">open(<span class="cm-string">‘my_json,txt‘,<span class="cm-string">‘r‘)<span class="cm-keyword">as <span class="cm-variable">f:<br><span><span class="cm-tab">        <span class="cm-variable">result=<span class="cm-variable">json.<span class="cm-property">load(<span class="cm-variable">f)<br><span><span class="cm-tab">        <span class="cm-builtin">print(<span class="cm-builtin">type(<span class="cm-variable">result))<br><span><span class="cm-tab">        <span class="cm-builtin">print(<span class="cm-variable">result[<span class="cm-string">‘feature‘][<span class="cm-number">2])<br><span class="cm-tab-wrap-hack"><span class="cm-tab">    <br><span><span class="cm-tab">    <span class="cm-keyword">with <span class="cm-builtin">open(<span class="cm-string">‘my_json,txt‘,<span class="cm-string">‘rb‘)<span class="cm-keyword">as <span class="cm-variable">f:<br><span><span class="cm-tab">        <span class="cm-variable">result=<span class="cm-variable">base64.<span class="cm-property">b64encode(<span class="cm-variable">f.<span class="cm-property">read())<br><span class="cm-tab-wrap-hack"><span class="cm-tab">    <br><span><span class="cm-tab">    <span class="cm-keyword">with <span class="cm-builtin">open(<span class="cm-string">‘my_json,txt‘,<span class="cm-string">‘wb‘)<span class="cm-keyword">as <span class="cm-variable">f:<br><span><span class="cm-tab">        <span class="cm-variable">f.<span class="cm-property">write(<span class="cm-variable">result)<br><span class="cm-tab-wrap-hack"><span class="cm-tab">    <br><span><span class="cm-tab">    <span class="cm-keyword">with <span class="cm-builtin">open(<span class="cm-string">‘my_json,txt‘,<span class="cm-string">‘rb‘)<span class="cm-keyword">as <span class="cm-variable">f:<br><span><span class="cm-tab">        <span class="cm-builtin">print(<span class="cm-variable">base64.<span class="cm-property">b64decode(<span class="cm-variable">f.<span class="cm-property">read()).<span class="cm-property">decode())<br><span><span>?<br><span><span>?</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

Python数据库 5.json,hashlib,base64模块

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