python常用模块

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)

• 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

  1 2 3 4 5 6 7 8 9 10 11 12 13 14

  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：

  1 2 3 4 5 6 7 8

  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

  

  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()

  

  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 i 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