python常用模块

模块,用一砣代码实现了某个功能的代码集合。 

类似于函数式编程和面向过程编程,函数式编程则完成一个功能,其他代码用来调用即可,提供了代码的重用性和代码间的耦合。而对于一个复杂的功能来,可能需要多个函数才能完成(函数又可以在不同的.py文件中),n个 .py 文件组成的代码集合就称为模块。

如:os 是系统相关的模块;file是文件操作相关的模块

内置模块

1、OS

用于提供系统级别的操作

os.getcwd() 获取当前工作目录,即当前python脚本工作的目录路径
os.chdir("dirname")  改变当前脚本工作目录;相当于shell下cd
os.curdir  返回当前目录: ('.')
os.pardir  获取当前目录的父目录字符串名:('..')
os.makedirs('dirname1/dirname2')    可生成多层递归目录
os.removedirs('dirname1')    若目录为空,则删除,并递归到上一级目录,如若也为空,则删除,依此类推
os.mkdir('dirname')    生成单级目录;相当于shell中mkdir dirname
os.rmdir('dirname')    删除单级空目录,若目录不为空则无法删除,报错;相当于shell中rmdir dirname
os.listdir('dirname')    列出指定目录下的所有文件和子目录,包括隐藏文件,并以列表方式打印
os.remove()  删除一个文件
os.rename("oldname","newname")  重命名文件/目录
os.stat('path/filename')  获取文件/目录信息
os.sep    输出操作系统特定的路径分隔符,win下为"\\",Linux下为"/"
os.linesep    输出当前平台使用的行终止符,win下为"\t\n",Linux下为"\n"
os.pathsep    输出用于分割文件路径的字符串
os.name    输出字符串指示当前使用平台。win->'nt'; Linux->'posix'
os.system("bash command")  运行shell命令,直接显示
os.environ  获取系统环境变量
os.path.abspath(path)  返回path规范化的绝对路径
os.path.split(path)  将path分割成目录和文件名二元组返回
os.path.dirname(path)  返回path的目录。其实就是os.path.split(path)的第一个元素
os.path.basename(path)  返回path最后的文件名。如何path以/或\结尾,那么就会返回空值。即os.path.split(path)的第二个元素
os.path.exists(path)  如果path存在,返回True;如果path不存在,返回False
os.path.isabs(path)  如果path是绝对路径,返回True
os.path.isfile(path)  如果path是一个存在的文件,返回True。否则返回False
os.path.isdir(path)  如果path是一个存在的目录,则返回True。否则返回False
os.path.join(path1[, path2[, ...]])  将多个路径组合后返回,第一个绝对路径之前的参数将被忽略
os.path.getatime(path)  返回path所指向的文件或者目录的最后存取时间
os.path.getmtime(path)  返回path所指向的文件或者目录的最后修改时间
更多模块访问:https://docs.python.org/2/library/os.html?highlight=os#module-os

二、sys
用于提供对解释器相关的操作
sys.argv           命令行参数List,第一个元素是程序本身路径
sys.exit(n)        退出程序,正常退出时exit(0)
sys.version        获取Python解释程序的版本信息
sys.maxint         最大的Int值
sys.path           返回模块的搜索路径,初始化时使用PYTHONPATH环境变量的值
sys.platform       返回操作系统平台名称
sys.stdout.write('please:')
val = sys.stdin.readline()[:-1]

三、hashlib
用于加密相关的操作,代替了md5模块和sha模块,主要提供SHA1,SHA224,SHA256,SHA384,SHA512,MD5算法

废弃
MD5
import md5
hash = md5.new()
hash.update('admin')
print hash.hexdigest()

SHA
import sha

hash = sha.new()
hash.update('admin')
print hash.hexdigest()

import hashlib
 
# ######## md5 ########
 
hash = hashlib.md5()
hash.update('admin')
print hash.hexdigest()
 
# ######## sha1 ########
 
hash = hashlib.sha1()
hash.update('admin')
print hash.hexdigest()
 
# ######## sha256 ########
 
hash = hashlib.sha256()
hash.update('admin')
print hash.hexdigest()
 
 
# ######## sha384 ########
 
hash = hashlib.sha384()
hash.update('admin')
print hash.hexdigest()
 
# ######## sha512 ########
 
hash = hashlib.sha512()
hash.update('admin')
print hash.hexdigest()
 
以上加密算法虽然依然非常厉害,但时候存在缺陷,即:通过撞库可以反解。所以,有必要对加密算法中添加自定义key再来做加密。
import hashlib
 
# ######## md5 ########
 
hash = hashlib.md5('898oaFs09f')
hash.update('admin')
print hash.hexdigest()
 
还不够吊?python 还有一个 hmac 模块,它内部对我们创建 key 和 内容 再进行处理然后再加密
import hmac
h = hmac.new('wueiqi')
h.update('hellowo')
print h.hexdigest()
 
四、json和pickle

用于序列化的两个模块

  • json,用于字符串 和 python数据类型间进行转换
  • pickle,用于python特有的类型 和 python的数据类型间进行转换

Json模块提供了四个功能:dumps、dump、loads、load

pickle模块提供了四个功能:dumps、dump、loads、load

 

例:

import pickle

data = {‘k1’:123,’k2’:Hello}

#pickle.dumps 将数据通过特殊的形式转换为只有python语言认识的字符串

p_str =pickle.dumps(data)

print(p_str)

#pickle.dump将数据通过特殊的形式转换为只有python语言认识的字符串,并写入文件

with open(‘D:\result.pk’,’w’) as fp:

pickle.dump(data,fp)

 

import json

#json.dumps将数据通过特殊的形式转换为所有程序语言都认识的字符串

j_str = json.dumps(data)

print(j_str)

#json.dump将数据通过特殊的形式转换为所有程序语言都认识的字符串,并写入文件
with open(‘D:\result.json’,’w’) as fp:
json.dump(data,fp)
 
五、执行系统命令
可以执行shell命令的相关模块和函数有:
 
  • os.system
  • os.spawn*
  • os.popen*          --废弃
  • popen2.*           --废弃
  • commands.*      --废弃,3.x中被移除
  • 
    
    import commands
    result = commands.getoutput('cmd')
    result = commands.getstatus('cmd')
    result = commands.getstatusoutput('cmd’)
    以上执行shell命令的相关的模块和函数的功能均在 subprocess 模块中实现,并提供了更丰富的功能。

     

    call 

    执行命令,返回状态码

    1
    2
    ret = subprocess.call(["ls", "-l"], shell=False)
    ret = subprocess.call("ls -l", shell=True)

    shell = True ,允许 shell 命令是字符串形式

    check_call

    执行命令,如果执行状态码是 0 ,则返回0,否则抛异常

    1
    2
    subprocess.check_call(["ls", "-l"])
    subprocess.check_call("exit 1", shell=True)

    check_output

    执行命令,如果状态码是 0 ,则返回执行结果,否则抛异常

    1
    2
    subprocess.check_output(["echo", "Hello World!"])
    subprocess.check_output("exit 1", shell=True)

    subprocess.Popen(...)

    用于执行复杂的系统命令

    参数:

    • args:shell命令,可以是字符串或者序列类型(如:list,元组)
    • bufsize:指定缓冲。0 无缓冲,1 行缓冲,其他 缓冲区大小,负值 系统缓冲
    • stdin, stdout, stderr:分别表示程序的标准输入、输出、错误句柄
    • preexec_fn:只在Unix平台下有效,用于指定一个可执行对象(callable object),它将在子进程运行之前被调用
    • close_sfs:在windows平台下,如果close_fds被设置为True,则新创建的子进程将不会继承父进程的输入、输出、错误管道。
      所以不能将close_fds设置为True同时重定向子进程的标准输入、输出与错误(stdin, stdout, stderr)。
    • shell:同上
    • cwd:用于设置子进程的当前目录
    • env:用于指定子进程的环境变量。如果env = None,子进程的环境变量将从父进程中继承。
    • universal_newlines:不同系统的换行符不同,True -> 同意使用 \n
    • startupinfo与createionflags只在windows下有效
      将被传递给底层的CreateProcess()函数,用于设置子进程的一些属性,如:主窗口的外观,进程的优先级等等
     
    import subprocess
    ret1 = subprocess.Popen(["mkdir","t1"])
    ret2 = subprocess.Popen("mkdir t2", shell=True)
    
    

    终端输入的命令分为两种:

    • 输入即可得到输出,如:ifconfig
    • 输入进行某环境,依赖再输入,如:python
     
    代码1
    import subprocess
    obj = subprocess.Popen("mkdir t3", shell=True, cwd='/home/dev’,)
    
    
    代码2
    import subprocess
    
    obj = subprocess.Popen(["python"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    obj.stdin.write('print 1 \n ')
    obj.stdin.write('print 2 \n ')
    obj.stdin.write('print 3 \n ')
    obj.stdin.write('print 4 \n ')
    obj.stdin.close()
    
    cmd_out = obj.stdout.read()
    obj.stdout.close()
    cmd_error = obj.stderr.read()
    obj.stderr.close()
    
    代码三
    print cmd_out
    print cmd_error
    
    
    import subprocess
    
    obj = subprocess.Popen(["python"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    obj.stdin.write('print 1 \n ')
    obj.stdin.write('print 2 \n ')
    obj.stdin.write('print 3 \n ')
    obj.stdin.write('print 4 \n ')
    
    out_error_list = obj.communicate()
    print out_error_list
    
    
    代码四
    import subprocess
    
    obj = subprocess.Popen(["python"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    out_error_list = obj.communicate('print "hello"')
    print out_error_list
    
    
    更多在这里:https://docs.python.org/2/library/subprocess.html?highlight=subprocess#frequently-used-arguments
    
    
    六、shutil

    高级的 文件、文件夹、压缩包 处理模块

    shutil.copyfileobj(fsrc, fdst[, length])
    将文件内容拷贝到另一个文件中,可以部分内容

     

    def copyfileobj(fsrc, fdst, length=16*1024):
        """copy data from file-like object fsrc to file-like object fdst"""
        while 1:
            buf = fsrc.read(length)
            if not buf:
                break
            fdst.write(buf)
    shutil.copyfile(src, dst)
    拷贝文件
    def copyfile(src, dst):
        """Copy data from src to dst"""
        if _samefile(src, dst):
            raise Error("`%s` and `%s` are the same file" % (src, dst))
    
        for fn in [src, dst]:
            try:
                st = os.stat(fn)
            except OSError:
                # File most likely does not exist
                pass
            else:
                # XXX What about other special files? (sockets, devices...)
                if stat.S_ISFIFO(st.st_mode):
                    raise SpecialFileError("`%s` is a named pipe" % fn)
    
        with open(src, 'rb') as fsrc:
            with open(dst, 'wb') as fdst:
                copyfileobj(fsrc, fdst)
    
    
    shutil.copymode(src, dst)
    仅拷贝权限。内容、组、用户均不变
    def copymode(src, dst):
        """Copy mode bits from src to dst"""
        if hasattr(os, 'chmod'):
            st = os.stat(src)
            mode = stat.S_IMODE(st.st_mode)
            os.chmod(dst, mode)
    
    
    shutil.copystat(src, dst)
    拷贝状态的信息,包括:mode bits, atime, mtime, flags
    def copystat(src, dst):
        """Copy all stat info (mode bits, atime, mtime, flags) from src to dst"""
        st = os.stat(src)
        mode = stat.S_IMODE(st.st_mode)
        if hasattr(os, 'utime'):
            os.utime(dst, (st.st_atime, st.st_mtime))
        if hasattr(os, 'chmod'):
            os.chmod(dst, mode)
        if hasattr(os, 'chflags') and hasattr(st, 'st_flags'):
            try:
                os.chflags(dst, st.st_flags)
            except OSError, why:
                for err in 'EOPNOTSUPP', 'ENOTSUP':
                    if hasattr(errno, err) and why.errno == getattr(errno, err):
                        break
                else:
                    raise
    
    
    shutil.copy(src, dst)
    拷贝文件和权限
    def copy(src, dst):
        """Copy data and mode bits ("cp src dst").
    
        The destination may be a directory.
    
        """
        if os.path.isdir(dst):
            dst = os.path.join(dst, os.path.basename(src))
        copyfile(src, dst)
        copymode(src, dst)
    
    
    shutil.copy2(src, dst)
    拷贝文件和状态信息
    def copy2(src, dst):
        """Copy data and all stat info ("cp -p src dst").
    
        The destination may be a directory.
    
        """
        if os.path.isdir(dst):
            dst = os.path.join(dst, os.path.basename(src))
        copyfile(src, dst)
        copystat(src, dst)
    
    

    shutil.ignore_patterns(*patterns)
    shutil.copytree(src, dst, symlinks=False, ignore=None)
    递归的去拷贝文件

    例如:copytree(source, destination, ignore=ignore_patterns('*.pyc', 'tmp*’))

     

    def ignore_patterns(*patterns):
        """Function that can be used as copytree() ignore parameter.
    
        Patterns is a sequence of glob-style patterns
        that are used to exclude files"""
        def _ignore_patterns(path, names):
            ignored_names = []
            for pattern in patterns:
                ignored_names.extend(fnmatch.filter(names, pattern))
            return set(ignored_names)
        return _ignore_patterns
    
    def copytree(src, dst, symlinks=False, ignore=None):
        """Recursively copy a directory tree using copy2().
    
        The destination directory must not already exist.
        If exception(s) occur, an Error is raised with a list of reasons.
    
        If the optional symlinks flag is true, symbolic links in the
        source tree result in symbolic links in the destination tree; if
        it is false, the contents of the files pointed to by symbolic
        links are copied.
    
        The optional ignore argument is a callable. If given, it
        is called with the `src` parameter, which is the directory
        being visited by copytree(), and `names` which is the list of
        `src` contents, as returned by os.listdir():
    
            callable(src, names) -> ignored_names
    
        Since copytree() is called recursively, the callable will be
        called once for each directory that is copied. It returns a
        list of names relative to the `src` directory that should
        not be copied.
    
        XXX Consider this example code rather than the ultimate tool.
    
        """
        names = os.listdir(src)
        if ignore is not None:
            ignored_names = ignore(src, names)
        else:
            ignored_names = set()
    
        os.makedirs(dst)
        errors = []
        for name in names:
            if name in ignored_names:
                continue
            srcname = os.path.join(src, name)
            dstname = os.path.join(dst, name)
            try:
                if symlinks and os.path.islink(srcname):
                    linkto = os.readlink(srcname)
                    os.symlink(linkto, dstname)
                elif os.path.isdir(srcname):
                    copytree(srcname, dstname, symlinks, ignore)
                else:
                    # Will raise a SpecialFileError for unsupported file types
                    copy2(srcname, dstname)
            # catch the Error from the recursive copytree so that we can
            # continue with other files
            except Error, err:
                errors.extend(err.args[0])
            except EnvironmentError, why:
                errors.append((srcname, dstname, str(why)))
        try:
            copystat(src, dst)
        except OSError, why:
            if WindowsError is not None and isinstance(why, WindowsError):
                # Copying file access times may fail on Windows
                pass
            else:
                errors.append((src, dst, str(why)))
        if errors:
            raise Error, errors
    
    
    shutil.rmtree(path[, ignore_errors[, onerror]])
    递归的去删除文件
    def rmtree(path, ignore_errors=False, onerror=None):
        """Recursively delete a directory tree.
    
        If ignore_errors is set, errors are ignored; otherwise, if onerror
        is set, it is called to handle the error with arguments (func,
        path, exc_info) where func is os.listdir, os.remove, or os.rmdir;
        path is the argument to that function that caused it to fail; and
        exc_info is a tuple returned by sys.exc_info().  If ignore_errors
        is false and onerror is None, an exception is raised.
    
        """
        if ignore_errors:
            def onerror(*args):
                pass
        elif onerror is None:
            def onerror(*args):
                raise
        try:
            if os.path.islink(path):
                # symlinks to directories are forbidden, see bug #1669
                raise OSError("Cannot call rmtree on a symbolic link")
        except OSError:
            onerror(os.path.islink, path, sys.exc_info())
            # can't continue even if onerror hook returns
            return
        names = []
        try:
            names = os.listdir(path)
        except os.error, err:
            onerror(os.listdir, path, sys.exc_info())
        for name in names:
            fullname = os.path.join(path, name)
            try:
                mode = os.lstat(fullname).st_mode
            except os.error:
                mode = 0
            if stat.S_ISDIR(mode):
                rmtree(fullname, ignore_errors, onerror)
            else:
                try:
                    os.remove(fullname)
                except os.error, err:
                    onerror(os.remove, fullname, sys.exc_info())
        try:
            os.rmdir(path)
        except os.error:
            onerror(os.rmdir, path, sys.exc_info())
    
    
    shutil.move(src, dst)
    递归的去移动文件
    def move(src, dst):
        """Recursively move a file or directory to another location. This is
        similar to the Unix "mv" command.
    
        If the destination is a directory or a symlink to a directory, the source
        is moved inside the directory. The destination path must not already
        exist.
    
        If the destination already exists but is not a directory, it may be
        overwritten depending on os.rename() semantics.
    
        If the destination is on our current filesystem, then rename() is used.
        Otherwise, src is copied to the destination and then removed.
        A lot more could be done here...  A look at a mv.c shows a lot of
        the issues this implementation glosses over.
    
        """
        real_dst = dst
        if os.path.isdir(dst):
            if _samefile(src, dst):
                # We might be on a case insensitive filesystem,
                # perform the rename anyway.
                os.rename(src, dst)
                return
    
            real_dst = os.path.join(dst, _basename(src))
            if os.path.exists(real_dst):
                raise Error, "Destination path '%s' already exists" % real_dst
        try:
            os.rename(src, real_dst)
        except OSError:
            if os.path.isdir(src):
                if _destinsrc(src, dst):
                    raise Error, "Cannot move a directory '%s' into itself '%s'." % (src, dst)
                copytree(src, real_dst, symlinks=True)
                rmtree(src)
            else:
                copy2(src, real_dst)
                os.unlink(src)
    
    

    shutil.make_archive(base_name, format,...)

    创建压缩包并返回文件路径,例如:zip、tar

    • base_name: 压缩包的文件名,也可以是压缩包的路径。只是文件名时,则保存至当前目录,否则保存至指定路径,
      如:www                        =>保存至当前路径
      如:/Users/wupeiqi/www =>保存至/Users/wupeiqi/
    • format: 压缩包种类,“zip”, “tar”, “bztar”,“gztar”
    • root_dir: 要压缩的文件夹路径(默认当前目录)
    • owner: 用户,默认当前用户
    • group: 组,默认当前组
    • logger: 用于记录日志,通常是logging.Logger对象
     
    #将 /Users/wupeiqi/Downloads/test 下的文件打包放置当前程序目录
     
    import shutil
    ret = shutil.make_archive("wwwwwwwwww", 'gztar', root_dir='/Users/wupeiqi/Downloads/test')
     
     
    #将 /Users/wupeiqi/Downloads/test 下的文件打包放置 /Users/wupeiqi/目录
    import shutil
    ret = shutil.make_archive("/Users/wupeiqi/wwwwwwwwww", 'gztar', root_dir='/Users/wupeiqi/Downloads/test’)
     
     
    代码案例:
    def make_archive(base_name, format, root_dir=None, base_dir=None, verbose=0,
                     dry_run=0, owner=None, group=None, logger=None):
        """Create an archive file (eg. zip or tar).
    
        'base_name' is the name of the file to create, minus any format-specific
        extension; 'format' is the archive format: one of "zip", "tar", "bztar"
        or "gztar".
    
        'root_dir' is a directory that will be the root directory of the
        archive; ie. we typically chdir into 'root_dir' before creating the
        archive.  'base_dir' is the directory where we start archiving from;
        ie. 'base_dir' will be the common prefix of all files and
        directories in the archive.  'root_dir' and 'base_dir' both default
        to the current directory.  Returns the name of the archive file.
    
        'owner' and 'group' are used when creating a tar archive. By default,
        uses the current owner and group.
        """
        save_cwd = os.getcwd()
        if root_dir is not None:
            if logger is not None:
                logger.debug("changing into '%s'", root_dir)
            base_name = os.path.abspath(base_name)
            if not dry_run:
                os.chdir(root_dir)
    
        if base_dir is None:
            base_dir = os.curdir
    
        kwargs = {'dry_run': dry_run, 'logger': logger}
    
        try:
            format_info = _ARCHIVE_FORMATS[format]
        except KeyError:
            raise ValueError, "unknown archive format '%s'" % format
    
        func = format_info[0]
        for arg, val in format_info[1]:
            kwargs[arg] = val
    
        if format != 'zip':
            kwargs['owner'] = owner
            kwargs['group'] = group
    
        try:
            filename = func(base_name, base_dir, **kwargs)
        finally:
            if root_dir is not None:
                if logger is not None:
                    logger.debug("changing back to '%s'", save_cwd)
                os.chdir(save_cwd)
    
        return filename
    
    
    shutil 对压缩包的处理是调用 ZipFile 和 TarFile 两个模块来进行的,详细:
    import zipfile
    
    zipfile压缩解压
    # 压缩
    z = zipfile.ZipFile('laxi.zip', 'w')
    z.write('a.log')
    z.write('data.data')
    z.close()
    
    # 解压
    z = zipfile.ZipFile('laxi.zip', 'r')
    z.extractall()
    z.close()
    
    
    tarfile压缩解压
    import tarfile
    
    # 压缩
    tar = tarfile.open('your.tar','w')
    tar.add('/Users/wupeiqi/PycharmProjects/bbs2.zip', arcname='bbs2.zip')
    tar.add('/Users/wupeiqi/PycharmProjects/cmdb.zip', arcname='cmdb.zip')
    tar.close()
    
    # 解压
    tar = tarfile.open('your.tar','r')
    tar.extractall()  # 可设置解压地址
    tar.close()
    
    
    七、ConfigParser
    
    
    用于对特定的配置进行操作,当前模块的名称在 python 3.x 版本中变更为 configparser。
    import ConfigParser
     
    config = ConfigParser.ConfigParser()
    config.read('i.cfg')
     
    # ########## 读 ##########
    #secs = config.sections()
    #print secs
    #options = config.options('group2')
    #print options
     
    #item_list = config.items('group2')
    #print item_list
     
    #val = config.get('group1','key')
    #val = config.getint('group1','key')
     
    # ########## 改写 ##########
    #sec = config.remove_section('group1')
    #config.write(open('i.cfg', "w"))
     
    #sec = config.has_section('wupeiqi')
    #sec = config.add_section('wupeiqi')
    #config.write(open('i.cfg', "w"))
     
     
    #config.set('group2','k1',11111)
    #config.write(open('i.cfg', "w"))
     
    #config.remove_option('group2','age')
    #config.write(open('i.cfg', "w”))
     
    八、logging
     

    用于便捷记录日志且线程安全的模块

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    import logging
     
     
    logging.basicConfig(filename='log.log',
                        format='%(asctime)s - %(name)s - %(levelname)s -%(module)s:  %(message)s',
                        datefmt='%Y-%m-%d %H:%M:%S %p',
                        level=10)
     
    logging.debug('debug')
    logging.info('info')
    logging.warning('warning')
    logging.error('error')
    logging.critical('critical')
    logging.log(10,'log')

    对于等级:

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    CRITICAL = 50
    FATAL = CRITICAL
    ERROR = 40
    WARNING = 30
    WARN = WARNING
    INFO = 20
    DEBUG = 10
    NOTSET = 0

    只有大于当前日志等级的操作才会被记录。

     

    对于格式,有如下属性可是配置:

     

    九、time

    时间相关的操作,时间有三种表示方式:

    • 时间戳               1970年1月1日之后的秒,即:time.time()
    • 格式化的字符串    2014-11-11 11:11,    即:time.strftime('%Y-%m-%d')
    • 结构化时间          元组包含了:年、日、星期等... time.struct_time    即:time.localtime()
    print time.time()
    print time.mktime(time.localtime())
      
    print time.gmtime()    #可加时间戳参数
    print time.localtime() #可加时间戳参数
    print time.strptime('2014-11-11''%Y-%m-%d')
      
    print time.strftime('%Y-%m-%d'#默认当前时间
    print time.strftime('%Y-%m-%d',time.localtime()) #默认当前时间
    print time.asctime()
    print time.asctime(time.localtime())
    print time.ctime(time.time())
      
    import datetime
    '''
    datetime.date:表示日期的类。常用的属性有year, month, day
    datetime.time:表示时间的类。常用的属性有hour, minute, second, microsecond
    datetime.datetime:表示日期时间
    datetime.timedelta:表示时间间隔,即两个时间点之间的长度
    timedelta([days[, seconds[, microseconds[, milliseconds[, minutes[, hours[, weeks]]]]]]])
    strftime("%Y-%m-%d")
    '''
    import datetime
    print datetime.datetime.now()
    print datetime.datetime.now() - datetime.timedelta(days=5)
     
     

    十、re 

    re模块用于对python的正则表达式的操作。

    字符:

      . 匹配除换行符以外的任意字符
      \w 匹配字母或数字或下划线或汉字
      \s 匹配任意的空白符
      \d 匹配数字
      \b 匹配单词的开始或结束
      ^ 匹配字符串的开始
      $ 匹配字符串的结束

    次数:

      * 重复零次或更多次
      + 重复一次或更多次
      ? 重复零次或一次
      {n} 重复n次
      {n,} 重复n次或更多次
      {n,m} 重复n到m次

    IP:
    ^(25[0-5]|2[0-4]\d|[0-1]?\d?\d)(\.(25[0-5]|2[0-4]\d|[0-1]?\d?\d)){3}$
    手机号:
    ^1[3|4|5|8][0-9]\d{8}$

    1、match(pattern, string, flags=0)

    从起始位置开始根据模型去字符串中匹配指定内容,匹配单个

    • 正则表达式
    • 要匹配的字符串
    • 标志位,用于控制正则表达式的匹配方式
    import re
    
    obj = re.match('\d+', '123uuasf')
    if obj:
        print obj.group()

    2、search(pattern, string, flags=0)

    根据模型去字符串中匹配指定内容,匹配单个

    import re
    
    obj = re.search('\d+', 'u123uu888asf')
    if obj:
        print obj.group()

    3、group和groups

    复制代码
    a = "123abc456"
    print re.search("([0-9]*)([a-z]*)([0-9]*)", a).group()
    
    print re.search("([0-9]*)([a-z]*)([0-9]*)", a).group(0)
    print re.search("([0-9]*)([a-z]*)([0-9]*)", a).group(1)
    print re.search("([0-9]*)([a-z]*)([0-9]*)", a).group(2)
    
    print re.search("([0-9]*)([a-z]*)([0-9]*)", a).groups()
    复制代码

    4、findall(pattern, string, flags=0)

    上述两中方式均用于匹配单值,即:只能匹配字符串中的一个,如果想要匹配到字符串中所有符合条件的元素,则需要使用 findall。

    import re
    
    obj = re.findall('\d+', 'fa123uu888asf')
    print obj

    5、sub(pattern, repl, string, count=0, flags=0)

    用于替换匹配的字符串

    content = "123abc456"
    new_content = re.sub('\d+', 'sb', content)
    # new_content = re.sub('\d+', 'sb', content, 1)
    print new_content

    相比于str.replace功能更加强大

    6、split(pattern, string, maxsplit=0, flags=0)

    根据指定匹配进行分组

    content = "'1 - 2 * ((60-30+1*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2) )'"
    new_content = re.split('\*', content)
    # new_content = re.split('\*', content, 1)
    print new_content
    content = "'1 - 2 * ((60-30+1*(9-2*5/3+7/3*99/4*2998+10*568/14))-(-4*3)/(16-3*2) )'"
    new_content = re.split('[\+\-\*\/]+', content)
    # new_content = re.split('\*', content, 1)
    print new_content
    inpp = '1-2*((60-30 +(-40-5)*(9-2*5/3 + 7 /3*99/4*2998 +10 * 568/14 )) - (-4*3)/ (16-3*2))'
    inpp = re.sub('\s*','',inpp)
    new_content = re.split('\(([\+\-\*\/]?\d+[\+\-\*\/]?\d+){1}\)', inpp, 1)
    print new_content

    相比于str.split更加强大 

    计算器原码:http://www.cnblogs.com/wupeiqi/articles/4949995.html

     

    十一、random

    随机数

    mport random
    print random.random()
    print random.randint(1,2)
    print random.randrange(1,10)


    随机验证码实例:

    import random
    checkcode = ''
    for in range(4):
        current = random.randrange(0,4)
        if current != i:
            temp = chr(random.randint(65,90))
        else:
            temp = random.randint(0,9)
        checkcode += str(temp)
    print checkcode
     
    此文档采用:http://www.cnblogs.com/wupeiqi/articles/4963027.html
posted @ 2017-04-09 16:22  Tale_G  阅读(257)  评论(0编辑  收藏  举报