Python中shutil模块的常用文件操作函数用法示例

Python  /  管理员 发布于 7年前   241

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)

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 shutilf1=open('name','r')f2=open('name_copy','w+')shutil.copyfileobj(f1,f2,length=16*1024)

 
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? (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

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

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))

先看两个文件的权限

[root@slyoyo python_test]# ls -ltotal 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

运行命令

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

查看结果

[root@slyoyo python_test]# ls -ltotal 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

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'

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)

 
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

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

 
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

[root@slyoyo python_test]# tree copytree_test/copytree_test/└── test  ├── test1  ├── test2  └── hahaha[root@slyoyo test]# ls -ltotal 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 -ltotal 12drwxr-xr-x. 3 root  root  4096 May 14 19:36 copytree_copydrwxr-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

 
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)

 
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

 
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

 
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 -ltotal 12drwxr-xr-x. 3 root  root  4096 May 14 19:36 copytree_copydrwxr-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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