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Python中shutil模块的常用文件操作函数用法示例

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Jul 22, 2016 am 08:56 AM

python shutil 文件

os模块提供了对目录或者文件的新建/删除/查看文件属性，还提供了对文件以及目录的路径操作。比如说：绝对路径，父目录…… 但是，os文件的操作还应该包含移动复制打包压缩解压等操作，这些os模块都没有提供。
而本文所讲的shutil则就是对os中文件操作的补充。--移动复制打包压缩解压，
shutil函数功能：
1 shutil.copyfileobj(fsrc, fdst[, length=16*1024])
copy文件内容到另一个文件，可以copy指定大小的内容
先来看看其源代码。

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)

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注意！在其中fsrc，fdst都是文件对象，都需要打开后才能进行复制操作

import shutil
f1=open('name','r')
f2=open('name_copy','w+')
shutil.copyfileobj(f1,f2,length=16*1024)

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2 shutil.copyfile(src,dst)
copy文件内容，是不是感觉上面的文件复制很麻烦？还需要自己手动用open函数打开文件，在这里就不需要了，事实上，copyfile调用了copyfileobj

def copyfile(src, dst, *, follow_symlinks=True):
  if _samefile(src, dst):
    raise SameFileError("{!r} and {!r} are the same file".format(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&#63; (sockets, devices...)
      if stat.S_ISFIFO(st.st_mode):
        raise SpecialFileError("`%s` is a named pipe" % fn)
  if not follow_symlinks and os.path.islink(src):
    os.symlink(os.readlink(src), dst)
  else:
    with open(src, 'rb') as fsrc:
      with open(dst, 'wb') as fdst:
        copyfileobj(fsrc, fdst)
  return dst

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shutil.copyfile('name','name_copy_2')
#一句就可以实现复制文件内容

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3 shutil.copymode(src,dst)
仅copy权限，不更改文件内容，组和用户。

def copymode(src, dst, *, follow_symlinks=True):
  if not follow_symlinks and os.path.islink(src) and os.path.islink(dst):
    if hasattr(os, 'lchmod'):
      stat_func, chmod_func = os.lstat, os.lchmod
    else:
      return
  elif hasattr(os, 'chmod'):
    stat_func, chmod_func = os.stat, os.chmod
  else:
    return
  st = stat_func(src)
  chmod_func(dst, stat.S_IMODE(st.st_mode))

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先看两个文件的权限

[root@slyoyo python_test]# ls -l
total 4
-rw-r--r--. 1 root root 79 May 14 05:17 test1
-rwxr-xr-x. 1 root root 0 May 14 19:10 test2

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运行命令

>>> import shutil
>>> shutil.copymode('test1','test2')

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查看结果

[root@slyoyo python_test]# ls -l
total 4
-rw-r--r--. 1 root root 79 May 14 05:17 test1
-rw-r--r--. 1 root root 0 May 14 19:10 test2

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当我们将目标文件换为一个不存在的文件时报错

>>> shutil.copymode('test1','test3')  
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
 File "/usr/local/python/lib/python3.4/shutil.py", line 132, in copymode
  chmod_func(dst, stat.S_IMODE(st.st_mode))
FileNotFoundError: [Errno 2] No such file or directory: 'test233'

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4 shutil.copystat(src,dst)
复制所有的状态信息，包括权限，组，用户，时间等

def copystat(src, dst, *, follow_symlinks=True):

  def _nop(*args, ns=None, follow_symlinks=None):
    pass
  # follow symlinks (aka don't not follow symlinks)
  follow = follow_symlinks or not (os.path.islink(src) and os.path.islink(dst))
  if follow:
    # use the real function if it exists
    def lookup(name):
      return getattr(os, name, _nop)
  else:
    # use the real function only if it exists
    # *and* it supports follow_symlinks
    def lookup(name):
      fn = getattr(os, name, _nop)
      if fn in os.supports_follow_symlinks:
        return fn
      return _nop
  st = lookup("stat")(src, follow_symlinks=follow)
  mode = stat.S_IMODE(st.st_mode)
  lookup("utime")(dst, ns=(st.st_atime_ns, st.st_mtime_ns),
    follow_symlinks=follow)
  try:
    lookup("chmod")(dst, mode, follow_symlinks=follow)
  except NotImplementedError:
    # if we got a NotImplementedError, it's because
    #  * follow_symlinks=False,
    #  * lchown() is unavailable, and
    #  * either
    #    * fchownat() is unavailable or
    #    * fchownat() doesn't implement AT_SYMLINK_NOFOLLOW.
    #     (it returned ENOSUP.)
    # therefore we're out of options--we simply cannot chown the
    # symlink. give up, suppress the error.
    # (which is what shutil always did in this circumstance.)
    pass
  if hasattr(st, 'st_flags'):
    try:
      lookup("chflags")(dst, st.st_flags, follow_symlinks=follow)
    except OSError as why:
      for err in 'EOPNOTSUPP', 'ENOTSUP':
        if hasattr(errno, err) and why.errno == getattr(errno, err):
          break
      else:
        raise
  _copyxattr(src, dst, follow_symlinks=follow)

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5 shutil.copy(src,dst)
复制文件的内容以及权限，先copyfile后copymode

 def copy(src, dst, *, follow_symlinks=True):

  if os.path.isdir(dst):
    dst = os.path.join(dst, os.path.basename(src))
  copyfile(src, dst, follow_symlinks=follow_symlinks)
  copymode(src, dst, follow_symlinks=follow_symlinks)
  return dst

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6 shutil.copy2(src,dst)
复制文件的内容以及文件的所有状态信息。先copyfile后copystat

def copy2(src, dst, *, follow_symlinks=True):
  """Copy data and all stat info ("cp -p src dst"). Return the file's
  destination."
  The destination may be a directory.
  If follow_symlinks is false, symlinks won't be followed. This
  resembles GNU's "cp -P src dst".
  """
  if os.path.isdir(dst):
    dst = os.path.join(dst, os.path.basename(src))
  copyfile(src, dst, follow_symlinks=follow_symlinks)
  copystat(src, dst, follow_symlinks=follow_symlinks)
  return dst

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7 shutil.copytree(src, dst, symlinks=False, ignore=None, copy_function=copy2,ignore_dangling_symlinks=False)
递归的复制文件内容及状态信息

def copytree(src, dst, symlinks=False, ignore=None, copy_function=copy2,
       ignore_dangling_symlinks=False):

  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 os.path.islink(srcname):
        linkto = os.readlink(srcname)
        if symlinks:
          # We can't just leave it to `copy_function` because legacy
          # code with a custom `copy_function` may rely on copytree
          # doing the right thing.
          os.symlink(linkto, dstname)
          copystat(srcname, dstname, follow_symlinks=not symlinks)
        else:
          # ignore dangling symlink if the flag is on
          if not os.path.exists(linkto) and ignore_dangling_symlinks:
            continue
          # otherwise let the copy occurs. copy2 will raise an error
          if os.path.isdir(srcname):
            copytree(srcname, dstname, symlinks, ignore,
                 copy_function)
          else:
            copy_function(srcname, dstname)
      elif os.path.isdir(srcname):
        copytree(srcname, dstname, symlinks, ignore, copy_function)
      else:
        # Will raise a SpecialFileError for unsupported file types
        copy_function(srcname, dstname)
    # catch the Error from the recursive copytree so that we can
    # continue with other files
    except Error as err:
      errors.extend(err.args[0])
    except OSError as why:
      errors.append((srcname, dstname, str(why)))
  try:
    copystat(src, dst)
  except OSError as why:
    # Copying file access times may fail on Windows
    if getattr(why, 'winerror', None) is None:
      errors.append((src, dst, str(why)))
  if errors:
    raise Error(errors)
  return dst
# version vulnerable to race conditions

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[root@slyoyo python_test]# tree copytree_test/
copytree_test/
└── test
  ├── test1
  ├── test2
  └── hahaha
[root@slyoyo test]# ls -l
total 0
-rw-r--r--. 1 python python 0 May 14 19:36 hahaha
-rw-r--r--. 1 python python 0 May 14 19:36 test1
-rw-r--r--. 1 root  root  0 May 14 19:36 test2
>>> shutil.copytree('copytree_test','copytree_copy')
'copytree_copy'
[root@slyoyo python_test]# ls -l
total 12
drwxr-xr-x. 3 root  root  4096 May 14 19:36 copytree_copy
drwxr-xr-x. 3 root  root  4096 May 14 19:36 copytree_test
-rw-r--r--. 1 python python  79 May 14 05:17 test1
-rw-r--r--. 1 root  root   0 May 14 19:10 test2
[root@slyoyo python_test]# tree copytree_copy/
copytree_copy/
└── test
  ├── hahaha
  ├── test1
  └── test2

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8 shutil.rmtree(path, ignore_errors=False, onerror=None)
递归地删除文件

def rmtree(path, ignore_errors=False, onerror=None):

  if ignore_errors:
    def onerror(*args):
      pass
  elif onerror is None:
    def onerror(*args):
      raise
  if _use_fd_functions:
    # While the unsafe rmtree works fine on bytes, the fd based does not.
    if isinstance(path, bytes):
      path = os.fsdecode(path)
    # Note: To guard against symlink races, we use the standard
    # lstat()/open()/fstat() trick.
    try:
      orig_st = os.lstat(path)
    except Exception:
      onerror(os.lstat, path, sys.exc_info())
      return
    try:
      fd = os.open(path, os.O_RDONLY)
    except Exception:
      onerror(os.lstat, path, sys.exc_info())
      return
    try:
      if os.path.samestat(orig_st, os.fstat(fd)):
        _rmtree_safe_fd(fd, path, onerror)
        try:
          os.rmdir(path)
        except OSError:
          onerror(os.rmdir, path, sys.exc_info())
      else:
        try:
          # 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())
    finally:
      os.close(fd)
  else:
    return _rmtree_unsafe(path, onerror)

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9 shutil.move(src, dst)
递归的移动文件

def move(src, dst):

  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.islink(src):
      linkto = os.readlink(src)
      os.symlink(linkto, real_dst)
      os.unlink(src)
    elif 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)
  return real_dst

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10 make_archive(base_name, format, root_dir=None, base_dir=None, verbose=0,dry_run=0, owner=None, group=None, logger=None)

压缩打包

def make_archive(base_name, format, root_dir=None, base_dir=None, verbose=0,
         dry_run=0, owner=None, group=None, logger=None):

  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

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base_name：压缩打包后的文件名或者路径名
format：压缩或者打包格式 "zip", "tar", "bztar"or "gztar"
root_dir : 将哪个目录或者文件打包（也就是源文件）

>>> shutil.make_archive('tarball','gztar',root_dir='copytree_test')
[root@slyoyo python_test]# ls -l
total 12
drwxr-xr-x. 3 root  root  4096 May 14 19:36 copytree_copy
drwxr-xr-x. 3 root  root  4096 May 14 19:36 copytree_test
-rw-r--r--. 1 root  root   0 May 14 21:12 tarball.tar.gz
-rw-r--r--. 1 python python  79 May 14 05:17 test1
-rw-r--r--. 1 root  root   0 May 14 19:10 test2

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