学习17.内容# 1.序列化 # 2.os # 3.sys # # 4.摘要 # 5.collections

序列化

什么是序列化 -- json
lit = [1, 2, 3, 4, 5,]
_lit= str(lit)
print(_lit)
print(list(_lit))
print(eval(_lit))

import json

两组四个方法
1.dumps loads
2.dump load
lit = [1, 2, 3, 4, 5, ]

_lst = json.dumps(lit)
print(_lst,type(_lst))
lis = json.loads(_lst)
print(lis,type(_lst))

lit = {'A': 1, 'B': 2, 'C': 3, }
_lst = json.dumps(lit)
_lst = json.dumps(lit,ensure_ascii=False)
print(_lst, type(_lst))
lis = json.loads(_lst)
print(lis, type(_lst))

import json

lit = {'A': 1, 'B': 2, 'C': 3, }
lit = [1, 2, 3, 4, 5, 6]
f = open('info', 'a', encoding='utf-8')
json.dump(lit, f)
f.close()

f1 = open("info", 'r', encoding="utf-8")
for i in f1:
    i = json.loads(i)
    print(i)
f1.close()
dump:将对象转换(序列化)成字符串,写入文件
liad:
pickle 序列化--(python所有对象进行转换)
唯一的区别是转换成特殊符号
import pickle
def func():
    print(123)
lit = [1, 2, 3, 4, 5, 6]
_list= pickle.dumps(lit)
print(_list)
print(pickle.loads(func()))

什么是序列化 -- json
lit = [1,22,3,3,45]  # [1,22,3,3,45]
s_lst = str(lit)
print(s_lst,type(s_lst))
print(list(s_lst))
print(eval(s_lst))  # 禁止使用

import json
两组4个方法:
    1.dumps loads
            lit = [1,22,3,3,45]
            print(json.dumps(lit),type(json.dumps(lit)))
            str_lst = json.dumps(lit)
            lst = json.loads(str_lst)
            print(lst,type(lst))

            dumps 将对象转换(序列化)成字符串
            loads 将字符串转换(反序列化)成对象

            dic = {'username':'宝元'}
            str_dic = json.dumps(dic)  # 序列化
            str_dic = json.dumps(dic,ensure_ascii=False)  # ensure_ascii=False 关闭ascii码
            print(str_dic,type(str_dic))
            dic1 = json.loads(str_dic)  # 反序列化
            print(dic1,dic1["username"])

    2.dump load
            import json
            lit = [1,22,3,3,45]
            同时写多个内容 进行序列化
            lst = [1,2,3,4,56,]
            f = open("info","w",encoding="utf-8")
            f.write(json.dumps(lst) + "\n")
            f.write(json.dumps(lst) + "\n")
            f.write(json.dumps(lst) + "\n")
            f.write(json.dumps(lst) + "\n")
            f.write(json.dumps(lst) + "\n")
            f.close()

            dump: 将对象转换(序列化)成字符串,写入文件
            load: 将文件中字符串转换(反序列)成对象

            同时读多个内容进行反序列
            f1 = open("info","r",encoding="utf-8")
            for i in f1:
                l = json.loads(i)
                print(l)
            f1.close()

pickle 序列化 - nb(python所有对象进行转换)
python自带的(只有python可以用)
两组4个方法:
1. dumps loads
        import pickle

        lst = [12,3,4,5,768]
        t_list = pickle.dumps(lst) # 转换成类似字节
        print(t_list)
        print(pickle.loads(t_list)[-1])

        dic = {"user":"郭宝元"}
        t_list = pickle.dumps(dic) # 转换成类似字节
        print(t_list)
        print(pickle.loads(t_list))

        def func():
            print(111)

        import json
        fun = json.dumps(func)
        print(fun)

        fun = pickle.dumps(func)
        print(fun)
        pickle.loads(fun)()

2. dump  load
import pickle
dic = {"usern":"baoyuian"}
dic = {"usern":"宝元"}
pickle.dump(dic,open("info","wb"))
print(pickle.load(open("info","rb")))

import pickle
dic = {"user":"123"}
pickle.dump(dic,open("info","ab"))

import pickle
dic = {"1":2}
f = open("info","wb")
s = "\n".encode("utf-8")
f.write(pickle.dumps(dic)+ s)
f.write(pickle.dumps(dic)+ s)
f.write(pickle.dumps(dic)+ s)
f.close()

f1 = open("info","rb")
for i in f1:
    print(pickle.loads(i))

推荐使用json
  json是各种语言通用的
  pickle(python私有)
asdfasd

os

import sys
print(sys.platform)

os 模块 -- 程序员通过python向操作系统发送指令(与操作系统交互的接口)
os模块四组:
    1.工作目录
            import os
            print(os.getcwd()) # 当前工作路径  ***
            os.chdir("F:\s24\day06") # 路径切换
            print(os.curdir)  # 当前
            print(os.pardir)  # 父级

    2.文件夹
            import os
            os.mkdir("ttt") # 创建一个文件夹  ***
            os.rmdir("ttt") # 删除一个文件夹  ***
            os.makedirs("ttt/sss/ddd/ee")  # 递归创建文件夹     ***
            os.removedirs("ttt/sss/ddd/ee")  # 递归删除文件夹   ***
            print(os.listdir(r"F:\s24\day17"))  ***

    3.文件
            import os
            os.rename()  # 修改名字   ***
            os.remove("info") # 删除文件  ***

    4.路径
            import os
            print(os.path.abspath(r"01 今日内容.py"))  # 通过相对路径获取绝对路径  ***
            print(os.path.split(os.path.abspath(r"01 今日内容.py")))  #将路径以最后一个\切割(路径,文件名)
            print(os.path.dirname(r"F:\s24\day17\01 今日内容.py"))  # 获取路径 ***
            print(os.path.basename(r"F:\s24\day17\01 今日内容.py")) # 获取文件名 **
            print(os.path.exists(r"F:\s24\day17\01 今日内容.py"))  # 判断这个路径是否存在  ***
            print(os.path.isdir(r"F:\s24\day17"))     # 判断是不是路径  ***
            print(os.path.isfile(r"01 今日内容.py"))  # 判断是不是文件  ***
            print(os.path.isabs(r"F:\s24\day17\01 今日内容.py"))     # 判断是不是绝对路径
            print(os.path.join("D:\\\\","ttt","bbb"))                # 路径拼接 *****
            import time
            print(time.time())
            print(os.path.getatime(r"F:\s24\day17\04 序列化.py"))      # 最后的修改时间
            print(os.path.getctime(r"F:\s24\day17\04 序列化.py"))      # 最后的访问时间
            print(os.path.getmtime(r"F:\s24\day17\04 序列化.py"))      # 最后的访问时间
            print(os.path.getsize(r"F:\s24\day09"))                    # 获取当前文件的大小   ***

sys

sys -- 与python解释器交互的接口

import sys
if sys.argv[-1] == "alex":
    print("dsb")
else:
    print("李业dsb")

print(sys.argv[-1])  # *** 当前文件运行['F:/s24/day17/06 sys.py']

import sys
print(sys.exit(1))   #

import sys
print(sys.version)  # 获取解释器版本

import sys
print(sys.path)     # 添加自定义模块查找路径 *****

import sys
print(sys.platform)   # *** 区分操作系统然后进行相关逻辑操作

hashlib

hashlib 加密
加密和校验

alex:alex123
alex:23lw23jky321jh4gqyt1234gj8b7t  # 加密后
{"1234":23lw23jky321jh4gqyt1234gj8b7t}

md5,sha1,sha256,sha512
1.只要明文相同密文就是相同的
2.只要明文不相同密文就是不相同的
3.不能反逆(不能解密) -- md5中国人破解了

alex:alex123
alex:b75bd008d5fecb1f50cf026532e8ae67

print(len("b75bd008d5fecb1f50cf026532e8ae67"))

加密:
    1.加密的内容
    2.将要加密的内容转成字节

import hashlib
md5 = hashlib.md5()
md5.update("alex123".encode("utf-8"))
print(md5.hexdigest())

md5 = hashlib.md5()
md5.update("alex".encode("utf-8"))
print(md5.hexdigest())

md5 = hashlib.md5()
md5.update("alex123".encode("gbk"))
print(md5.hexdigest())

md5 = hashlib.md5()
md5.update("alex123".encode("shift-jis"))
print(md5.hexdigest())

import hashlib
sha1 = hashlib.sha256()
sha1.update("alex123".encode("utf-8"))
print(sha1.hexdigest())

md5 = hashlib.md5()
md5.update("alex123".encode("utf-8"))
print(md5.hexdigest())

最常用是的md5,平时加密的时候使用sha1

加盐

加固定盐
import hashlib
md5 = hashlib.md5("常鑫".encode("utf-8"))
md5.update("alex123".encode("utf-8"))
print(md5.hexdigest())

md5 = hashlib.md5()
md5.update("alex123".encode("utf-8"))
print(md5.hexdigest())

动态加盐

user = input("username:")
pwd = input("password")

import hashlib
md5 = hashlib.md5(user.encode("utf-8"))
md5.update(pwd.encode("utf-8"))
print(md5.hexdigest())

md5 = hashlib.md5()
md5.update(pwd.encode("utf-8"))
print(md5.hexdigest())

767db14ed07b245e24e10785f9d28e29

f = open(r"F:\s24\day17\python-3.6.6-amd64.exe","rb")
import hashlib
md5 = hashlib.md5()
md5.update(f.read())
print(md5.hexdigest())

ss = "baoyuanalextaibai"
s = "baoyuan"
s1 = "alex"
s2 = "taibai"
import hashlib
md5 = hashlib.md5()
md5.update(ss.encode("utf-8"))
print(md5.hexdigest())

md5 = hashlib.md5()
md5.update(s.encode("utf-8"))
md5.update(s1.encode("utf-8"))
md5.update(s2.encode("utf-8"))
print(md5.hexdigest())

节省内存

f = open(r"F:\s24\day17\python-3.6.6-amd64.exe","rb")
import hashlib
md5 = hashlib.md5()
while True:
    msg = f.read(1024)
    if msg:
        md5.update(msg)
    else:
        print(md5.hexdigest())
        break

collections

1.namedtuple: 生成可以使用名字来访问元素内容的tuple
2.deque: 双端队列，可以快速的从另外一侧追加和推出对象
3.Counter: 计数器，主要用来计数
4.OrderedDict: 有序字典
5.defaultdict: 带有默认值的字典

from collections import namedtuple,deque
Point = namedtuple('tu',["a","b","c"]) # 第一个参数是元组的名字,第二参数是元组中元素的[名字,名字]
p = Point({"keu":(1,2,3,4)}, 20,10)
print(p)
tu = (1,2,32,34,4)
print(tu)

lst = deque([1,2,3,4,5,6,7])
lst.append(8)
lst.appendleft(0)
lst.pop()
lst.popleft()
print(lst[4])

队列:先进先出
栈:先进后出  --  栈顶

lst = [1,2,3,4]
lst.append(5)
lst.pop(0)

5.defaultdict: 带有默认值的字典
from collections import defaultdict
dic = defaultdict(list)
dic["k1"].append(12)
print(dic)

li = [11,22,33,44,55,77,88,99,90]
result = {"key1":[],"key2":[]}
result = {}
for row in li:
    if row > 66:
        if 'key1' not in result:
            result['key1'] = []
        result['key1'].append(row)
    else:
        if 'key2' not in result:
            result['key2'] = []
        result['key2'].append(row)
print(result)

from collections import defaultdict
dic = defaultdict(set)
li = [11,22,33,44,55,77,88,99,90]
for i in li:
    if i > 66:
        dic["k1"].add(i)
    else:
        dic["k2"].add(i)
print(dic)

from collections import Counter
s = "1112233344aaa"
s = [1,1,2,2,3,3]
s = (1,2,3,3,4,5,6,7,78)
print(dict(Counter(s)))  # ***
统计元素出现的次数

原文地址：https://www.cnblogs.com/changxin7/p/11252139.html