python常见模块与用法_Python

一、常见内置模块

1.1什么叫做模块?

import XXXX
xxxxx就是模块 .py

1.2模块的分类

1.random
2.math
3.内置模块

1.3第三方的模块(需要安装)

在线安装 cmd 窗口下通过 pip install 模块名
python -m pip install 模块的名

离线安装下载好所需要的安装包 zip ---- 解压安装包 ------setup.py--------cmd : python install
setup.py

二、模块导入的问题

import 模块名

import random

import 模块名 as 别名

import random as r

from 包 import 模块的名称

from os import path

三、random模块

用来产生随机数（伪随机数）

[ ‘BPF", ‘LOG4", ‘NV_MAGICCONST", ‘RECIP_BPF", ‘Random", ‘SG_MAGICCONST", ‘SystemRandom",‘TWOPI", ‘Sequence", ‘Set", ‘all", ‘builtins", ‘cached", ‘doc", ‘file", ‘loader", ‘name", ‘package", ‘spec",‘accumulate", ‘acos", ‘bisect", ‘ceil", ‘cos", ‘e", ‘exp", ‘floor", ‘inst", ‘log", ‘os", ‘pi", ‘random", ‘repeat", ‘sha512",‘sin", ‘sqrt", ‘test", ‘test_generator", ‘urandom", ‘_warn", ‘betavariate", ‘choice", ‘choices", ‘expovariate",‘gammavariate", ‘gauss", ‘getrandbits", ‘getstate", ‘lognormvariate", ‘normalvariate", ‘paretovariate",‘randbytes", ‘randint", ‘random", ‘randrange", ‘sample", ‘seed", ‘setstate", ‘shuffle", ‘triangular",‘uniform", ‘vonmisesvariate", ‘weibullvariate" ]
主要常见的random模块的函数：

3.1randint() --------- 产生随机整数[m,n]

python常见模块与用法

3.2random() --------------产生0-1的随机数[0,1)

python常见模块与用法

3.3uniform() ------------- 产生正态分布的随机数

python常见模块与用法

3.4randrange() ------ 产生一个范围内的随机数

python常见模块与用法

3.5choices（） ---------- 用在序列（容器）（有序的序列）随机筛取一个元素

python常见模块与用法

四、math模块

用于数学运算

[‘doc", ‘loader", ‘name", ‘package", ‘spec", ‘acos", ‘acosh", ‘asin", ‘asinh", ‘atan", ‘atan2", ‘atanh",
‘ceil", ‘comb", ‘copysign", ‘cos", ‘cosh", ‘degrees", ‘dist", ‘e", ‘erf", ‘erfc", ‘exp", ‘expm1", ‘fabs", ‘factorial",
‘floor", ‘fmod", ‘frexp", ‘fsum", ‘gamma", ‘gcd", ‘hypot", ‘inf", ‘isclose", ‘isfinite", ‘isinf", ‘isnan", ‘isqrt",
‘lcm", ‘ldexp", ‘lgamma", ‘log", ‘log10", ‘log1p", ‘log2", ‘modf", ‘nan", ‘nextafter", ‘perm", ‘pi", ‘pow",
‘prod", ‘radians", ‘remainder", ‘sin", ‘sinh", ‘sqrt", ‘tan", ‘tanh", ‘tau", ‘trunc", ‘ulp"]

ceil ------------- 向上取整
floor ----------- 向下取整
e ------------ 属性自然常数
fabs ----------- 求绝对值等价 abs() 全局函数
fmod ----------- 求模运算
isnan -------- 判断是不是数字（是数字返回 false nan -----not a number）
isfinite ----- 判断是不是无限
pi ----------- 圆周率
pow ------------- 幂次方
sqrt ---------- 平方根

五、os模块

5.1操作系统文件

清屏的方法 --------- import os os.system(“cls”)
[‘DirEntry", ‘F_OK", ‘GenericAlias", ‘Mapping", ‘MutableMapping", ‘O_APPEND", ‘O_BINARY",
‘O_CREAT", ‘O_EXCL", ‘O_NOINHERIT", ‘O_RANDOM", ‘O_RDONLY", ‘O_RDWR", ‘O_SEQUENTIAL",
‘O_SHORT_LIVED", ‘O_TEMPORARY", ‘O_TEXT", ‘O_TRUNC", ‘O_WRONLY", ‘P_DETACH", ‘P_NOWAIT",‘P_NOWAITO", ‘P_OVERLAY", ‘P_WAIT", ‘PathLike", ‘R_OK", ‘SEEK_CUR", ‘SEEK_END", ‘SEEK_SET",‘TMP_MAX", ‘W_OK", ‘X_OK", ‘AddedDllDirectory", ‘Environ", ‘all", ‘builtins", ‘cached", ‘doc", ‘file",‘loader", ‘name", ‘package", ‘spec", ‘check_methods", ‘execvpe", ‘exists", ‘exit", ‘fspath",
‘get_exports_list", ‘walk", ‘wrap_close", ‘abc", ‘abort", ‘access", ‘add_dll_directory", ‘altsep", ‘chdir",
‘chmod", ‘close", ‘closerange", ‘cpu_count", ‘curdir", ‘defpath", ‘device_encoding", ‘devnull", ‘dup",
‘dup2", ‘environ", ‘error", ‘execl", ‘execle", ‘execlp", ‘execlpe", ‘execv", ‘execve", ‘execvp", ‘execvpe",
‘extsep", ‘fdopen", ‘fsdecode", ‘fsencode", ‘fspath", ‘fstat", ‘fsync", ‘ftruncate", ‘get_exec_path",
‘get_handle_inheritable", ‘get_inheritable", ‘get_terminal_size", ‘getcwd", ‘getcwdb", ‘getenv",
‘getlogin", ‘getpid", ‘getppid", ‘isatty", ‘kill", ‘linesep", ‘link", ‘listdir", ‘lseek", ‘lstat", ‘makedirs", ‘mkdir",
‘name", ‘open", ‘pardir", ‘path", ‘pathsep", ‘pipe", ‘popen", ‘putenv", ‘read", ‘readlink", ‘remove",
‘removedirs", ‘rename", ‘renames", ‘replace", ‘rmdir", ‘scandir", ‘sep", ‘set_handle_inheritable",
‘set_inheritable", ‘spawnl", ‘spawnle", ‘spawnv", ‘spawnve", ‘st", ‘startfile", ‘stat", ‘stat_result",
‘statvfs_result", ‘strerror", ‘supports_bytes_environ", ‘supports_dir_fd", ‘supports_effective_ids",
‘supports_fd", ‘supports_follow_symlinks", ‘symlink", ‘sys", ‘system", ‘terminal_size", ‘times",
‘times_result", ‘truncate", ‘umask", ‘uname_result", ‘unlink", ‘unsetenv", ‘urandom", ‘utime", ‘waitpid",
‘waitstatus_to_exitcode", ‘walk", ‘write"]

5.2os模块常用方法

chdir（） ------- 修改工作目录
curdir ------- 获取当前的目录返回的结果的是相对路径（绝对路径 os.path.abspath(os.curdir) ）
chmod() ---------修改权限
close -------- 关闭文件的路径
cpu_count（） --------- 返回的cpu的核对应得线程数
getcwd（） ----------获取当前路径，返回得是绝对路径，相当linux下pwd
getpid（）-------获取当前进程的进程编号
getppid（） ------------获取当前进程的父进程的进程编号
kill（） ------------- 通过进程编号杀死进程
linesep -------- 属性对应系统下的换行符
listdir（） ------ 返回的对应目录下所有的文件和文件夹（隐藏的文件夹），返回的是列表
makedirs（） ----- 创建目录，支持多层目录的创建
mkdir（） ----- 创建目录，只能创建一层，不支持多层
open（）------创建文件 open()全局函数
pathsep ------- 获取环境变量分隔符 windows ； linux分割符 :
sep --------- 获取路径分割符
remove（文件名或者路径） ----------删除文件
removedirs（） --------------- 删除目录，支持多级删除（递归）
system（）-------- 执行终端命令

5.3os.path模块

import os.path
import os.path as p
from os import path

[‘all", ‘builtins", ‘cached", ‘doc", ‘file", ‘loader", ‘name", ‘package", ‘spec", ‘abspath_fallback",
‘get_bothseps", ‘getfinalpathname", ‘getfinalpathname_nonstrict", ‘getfullpathname",
‘getvolumepathname", ‘nt_readlink", ‘readlink_deep", ‘abspath", ‘altsep", ‘basename", ‘commonpath",
‘commonprefix", ‘curdir", ‘defpath", ‘devnull", ‘dirname", ‘exists", ‘expanduser", ‘expandvars", ‘extsep",
‘genericpath", ‘getatime", ‘getctime", ‘getmtime", ‘getsize", ‘isabs", ‘isdir", ‘isfile", ‘islink", ‘ismount",
‘join", ‘lexists", ‘normcase", ‘normpath", ‘os", ‘pardir", ‘pathsep", ‘realpath", ‘relpath", ‘samefile",
‘sameopenfile", ‘samestat", ‘sep", ‘split", ‘splitdrive", ‘splitext", ‘stat", ‘supports_unicode_filenames",
‘sys"]

abspath(相对路径) ----------------- 返回的路径的所对应的绝对路径
altsep ------------------ 返回的python中的分隔符
basename ------------ 文件名称
dirname ----------- 文件目录
exists ---------------- 判断文件或者目录是否存在
getctime -------- 获取时间（创建时间）
getmtime ------------ 获取修改时间
getsize ------------ 获取文件的大小，单位是字节
isdir-------------- 判断path是否是目录（文件夹）
isfile-------------------判断path是否是文件
isabs ------------- 判断是不是绝对路径
islink ------- 判断是不是链接
ismount ---------- 判断是不是挂载文件
join -------------- 拼接路径
sep ----------- 路径分隔符
split ----------分割路径
relpath ------------- 返回的真正的路径和abspath一样

5.4练习

需要结合os.path 和 os 模块，以及函数的递归

给出一个路径，遍历当前路径所有文件和文件夹，打印出所有的文件（遇到文件输出路径，如果遇
到的文件夹继续遍历文件夹）

import os
from os import path
def scanner_file(url):
    files = os.listdir(url)
    #拼接路径
    for file in files:
        #real_path = url + "" + f
        real_path = path.join(url,file)
        #print (file)
        if path.isfile(real_path):
            l = path.abspath(real_path) # 把取出来的路径赋值给L
            print(l)#输出在屏幕上
        elif path.isdir(real_path):
            scanner_file(real_path)
        else:
            print("其他情况")
            pass
scanner_file("E:")

六、sys模块

[‘breakpointhook", ‘displayhook", ‘doc", ‘excepthook", ‘interactivehook", ‘loader", ‘name",
‘package", ‘spec", ‘stderr", ‘stdin", ‘stdout", ‘unraisablehook", ‘base_executable", ‘clear_type_cache",
‘current_frames", ‘debugmallocstats", ‘enablelegacywindowsfsencoding", ‘framework", ‘getframe", ‘git",
‘home", ‘xoptions", ‘addaudithook", ‘api_version", ‘argv", ‘audit", ‘base_exec_prefix", ‘base_prefix",
‘breakpointhook", ‘builtin_module_names", ‘byteorder", ‘call_tracing", ‘copyright", ‘displayhook",
‘dllhandle", ‘dont_write_bytecode", ‘exc_info", ‘excepthook", ‘exec_prefix", ‘executable", ‘exit", ‘flags",
‘float_info", ‘float_repr_style", ‘get_asyncgen_hooks", ‘get_coroutine_origin_tracking_depth",
‘getallocatedblocks", ‘getdefaultencoding", ‘getfilesystemencodeerrors", ‘getfilesystemencoding",
‘getprofile", ‘getrecursionlimit", ‘getrefcount", ‘getsizeof", ‘getswitchinterval", ‘gettrace",
‘getwindowsversion", ‘hash_info", ‘hexversion", ‘implementation", ‘int_info", ‘intern", ‘is_finalizing",
‘maxsize", ‘maxunicode", ‘meta_path", ‘modules", ‘path", ‘path_hooks", ‘path_importer_cache",
‘platform", ‘platlibdir", ‘prefix", ‘ps1", ‘ps2", ‘pycache_prefix", ‘set_asyncgen_hooks"
‘set_coroutine_origin_tracking_depth", ‘setprofile", ‘setrecursionlimit", ‘setswitchinterval", ‘settrace",
‘stderr", ‘stdin", ‘stdout", ‘thread_info", ‘unraisablehook", ‘version", ‘version_info", ‘warnoptions",
‘winver"]

api_version -------------- 属性获取python内部的版本号
argv --------- 接收脚本参数
copyright ------------ 输出cpython版本号
exit ---------- 退出系统
getdefaultencoding（）-------------获取的默认编码,python3默认编码是utf-8
getfilesystemencoding（）------------ 获取文件系统的默认编程，默认utf-8
getrecursionlimit（）------- 获取python对递归的限制层数
setrecursionlimit（） -------------重新设置递归的限制的层数
getrefcount（对象）--------- 获取对象的引用计数，是垃圾回收机制里的引用计数，注意任何对象都
有一个默认引用计数
getwindowsversion（） ---------- 获取当前窗口的版本信息
version -----------## 标题-- 获取版本信息

**python的垃圾回收机制：

以引用计数为主，以标记清除和分代收集为辅
Java 以标记清除为主，以引用计数和分代收集为辅 **

七、时间模块

7.1time模块

python提供操作日期和时间的模块

["_STRUCT_TM_ITEMS", ‘doc", ‘loader", ‘name", ‘package", ‘spec", ‘altzone", ‘asctime", ‘ctime",
‘daylight", ‘get_clock_info", ‘gmtime", ‘localtime", ‘mktime", ‘monotonic", ‘monotonic_ns",
‘perf_counter", ‘perf_counter_ns", ‘process_time", ‘process_time_ns", ‘sleep", ‘strftime", ‘strptime",
‘struct_time", ‘thread_time", ‘thread_time_ns", ‘time", ‘time_ns", ‘timezone", ‘tzname"]

asctime（） ------------ 获取当前时间
ctime（）------ 获取当前时间
localtime（）------ 获取的本地时间，返回的是对象
sleep（）-------- 表示休眠的时间，单位秒
time（）---------------- 获取当前系统的时间戳，单位也是秒
strftime（）------- 将时间对象格式化成字符串
strptime（）------将一个特定的时间字符串转换为时间对象

7.2datetime模块

对Time模块的补充

from datetime import datetime
[‘add", ‘class", ‘delattr", ‘dir", ‘doc", ‘eq", ‘format", ‘ge", ‘getattribute", ‘gt", ‘hash", ‘init",
‘init_subclass", ‘le", ‘lt", ‘ne", ‘new", ‘radd", ‘reduce", ‘reduce_ex", ‘repr", ‘rsub", ‘setattr", ‘sizeof",
‘str", ‘sub", ‘subclasshook", ‘astimezone", ‘combine", ‘ctime", ‘date", ‘day", ‘dst", ‘fold",
‘fromisocalendar", ‘fromisoformat", ‘fromordinal", ‘fromtimestamp", ‘hour", ‘isocalendar",
‘isoformat", ‘isoweekday", ‘max", ‘microsecond", ‘min", ‘minute", ‘month", ‘now", ‘replace", ‘resolution",
‘second", ‘strftime", ‘strptime", ‘time", ‘timestamp", ‘timetuple", ‘timetz", ‘today", ‘toordinal", ‘tzinfo",
‘tzname", ‘utcfromtimestamp", ‘utcnow", ‘utcoffset", ‘utctimetuple", ‘weekday", ‘year"]
now() ------------获取当前的时间

八、其他模块

日历的模块（calendar）

uuid 模块 ------------ 一般会用在文件上传或者文件备份的时候：

产生一个永不重复的字符串
uuid.uuid4().hex

练习：完成用户注册登录的案例（加盐值混淆）

import sys
import hashlib
users=[]
salt = "#!@$@!%^#&^!&!##@!"
def main():
    print("*~"*20)
    print("1.用户注册")
    print("2.用户登录")
    print("3.退出系统")
    print("*~"*20)
    choice = input("请选择对应想要的操作：")
    return choice

def register():
    username = input("请输入注册用户名:")
    passwd = input("请输入注册用户密码:")
    if username == None or username.strip() == "":
        print("用户名不能为空")
        return
    if passwd == None or passwd.strip()=="" or len(passwd) < 6:
        print("用户密码不能为空或者小于6位长度")
        return
    passwd = passwd_md5(passwd)
    for i in users:
        if i.get("username") == username:
            print("用户名重复")
            return
    user = {}
    user["username"] = username
    user["passwd"] = passwd
    users.append(user)
    print(users)

def passwd_md5(passwd):
    md5 = hashlib.md5(passwd.encode("utf-8"))
    md5.update(salt.encode("utf-8"))
    return md5.hexdigest()

def is_login(username,passwd):
    for i in users:
        if i.get("username") == username and i.get("passwd") == passwd:
            return True
        return False

def login():
    username = input("请输入登陆的用户名:")
    passwd = input("请输入登陆用户密码：")
    passwd = passwd_md5(passwd)
    if is_login(username,passwd):
        print("恭喜,登陆成功")
        print(users) /
    else:
        print("抱歉,登陆失败")

while(True):
    choice = main()
    if choice == "1":
        print("注册")
        register()
    elif choice =="2":
        print("登陆")
        login()
    elif choice =="3":
        print("退出系统......")
        sys.exit()

九、加密算法的介绍

有了解加密？加密是计算机中最重要的技术之一

分类：

以算法的是否可逆：

可逆算法

是不是使用同一密钥：

对称加密

解密和加密的时候使用同一个密钥

DES算法

不对称加密

加密和解密使用的是同一对密钥（公钥、私钥）https协议 RSA算法

不可逆算法（hash算法）

特点：不可逆、结果是唯一的

MD5

十、hashlib库

10.1哈希算法

import hashlib

使用步骤：

创建算法对象（md5 sha256）,返回的是算法对象
md5 = hashlib.md5()
md5
一个字符串加密的话md5 = hashlib.md5(“123”.encode(“utf-8”))
如果不做盐值混淆， md5.hexdigest()

盐值混淆

md5.update(盐值)

python常见模块与用法

盐值越复杂，加密的安全性就越高

cmd5.com 解密

10.2hmac库

也是一个哈希加密库，用到了对称加密
new()
参数:第一个参数是要加密的字符串，第二个参数盐值，第三个参数是加密算法
首先使用对称加密（密钥就是盐值），得到加密的结果之后又进行了一次hash加密（盐值混淆）

python常见模块与用法

十一、对象序列化

什么是对象序列化？

字典列表元组集合 -------------- 对象

序列化：将抽象的这些对象的概念转换真正的字符或者字节数据

十二、pickle模块

[‘ADDITEMS", ‘APPEND", ‘APPENDS", ‘BINBYTES", ‘BINBYTES8", ‘BINFLOAT", ‘BINGET", ‘BININT",
‘BININT1", ‘BININT2", ‘BINPERSID", ‘BINPUT", ‘BINSTRING", ‘BINUNICODE", ‘BINUNICODE8", ‘BUILD",‘BYTEARRAY8", ‘DEFAULT_PROTOCOL", ‘DICT", ‘DUP", ‘EMPTY_DICT", ‘EMPTY_LIST", ‘EMPTY_SET",‘EMPTY_TUPLE", ‘EXT1", ‘EXT2", ‘EXT4", ‘FALSE", ‘FLOAT", ‘FRAME", ‘FROZENSET", ‘FunctionType", ‘GET",‘GLOBAL", ‘HIGHEST_PROTOCOL", ‘INST", ‘INT", ‘LIST", ‘LONG", ‘LONG1", ‘LONG4", ‘LONG_BINGET",‘LONG_BINPUT", ‘MARK", ‘MEMOIZE", ‘NEWFALSE", ‘NEWOBJ", ‘NEWOBJ_EX", ‘NEWTRUE",‘NEXT_BUFFER", ‘NONE", ‘OBJ", ‘PERSID", ‘POP", ‘POP_MARK", ‘PROTO", ‘PUT", ‘PickleBuffer",‘PickleError", ‘Pickler", ‘PicklingError", ‘PyStringMap", ‘READONLY_BUFFER", ‘REDUCE", ‘SETITEM",‘SETITEMS", ‘SHORT_BINBYTES", ‘SHORT_BINSTRING", ‘SHORT_BINUNICODE", ‘STACK_GLOBAL",‘STOP", ‘STRING", ‘TRUE", ‘TUPLE", ‘TUPLE1", ‘TUPLE2", ‘TUPLE3", ‘UNICODE", ‘Unpickler",‘UnpicklingError", ‘Framer", ‘HAVE_PICKLE_BUFFER", ‘Pickler", ‘Stop", ‘Unframer", ‘Unpickler", ‘all",‘builtins", ‘cached", ‘doc", ‘file", ‘loader", ‘name", ‘package", ‘spec", ‘compat_pickle", ‘dump", ‘dumps",‘extension_cache", ‘extension_registry", ‘getattribute", ‘inverted_registry", ‘load", ‘loads", ‘test",
‘_tuplesize2code", ‘bytes_types", ‘codecs", ‘compatible_formats", ‘decode_long", ‘dispatch_table",
‘dump", ‘dumps", ‘encode_long", ‘format_version", ‘io", ‘islice", ‘load", ‘loads", ‘maxsize", ‘pack",
‘partial", ‘re", ‘sys", ‘unpack", ‘whichmodule"]

dumps -------------- 将对象序列化为字节数据 .dat

python常见模块与用法

loads -------------- 将数据反序列化为对象

users = [1,2,3,4,5]
data = pickle.dumps(users) # 将对象序列化
    f = open("a.txt","wb")
    f.write(data)
    f.close()
    f = open("a.dat","wb")
    f.write(data)
    f.close()
    f = open("a.dat","rb")
    show = f.read()
    print(data,"
")
    print("对象序列化为字节数据：",show,"
")
    print("将数据反序列化为对象：",pickle.loads(show),"
")  #将数据反序列化为对象

dump --------------将对象序列化为字节数据 ,并且保存到file

load -------------- 将数据反序列化为对象