Python lấy đường dẫn tệp từ explorer

Tên tệp, đối số dòng lệnh và biến môi trường

Trong Python, tên tệp, đối số dòng lệnh và biến môi trường được biểu diễn bằng kiểu chuỗi. Trên một số hệ thống, việc giải mã các chuỗi này đến và từ byte là cần thiết trước khi chuyển chúng đến hệ điều hành. Python sử dụng để thực hiện chuyển đổi này [xem ]

Được cấu hình khi khởi động Python bằng hàm

>>> import os
>>> statinfo = os.stat['somefile.txt']
>>> statinfo
os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027]
>>> statinfo.st_size
264

Đã thay đổi trong phiên bản 3. 1. Trên một số hệ thống, quá trình chuyển đổi bằng mã hóa hệ thống tệp có thể không thành công. Trong trường hợp này, Python sử dụng , có nghĩa là các byte không thể giải mã được thay thế bằng ký tự Unicode U+DCxx khi giải mã và chúng lại được dịch sang byte gốc khi mã hóa.

Phải đảm bảo giải mã thành công tất cả các byte dưới 128. Nếu mã hóa hệ thống tệp không cung cấp bảo đảm này, các chức năng API có thể tăng

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Chế độ Python UTF-8

New in version 3. 7. See PEP 540 for more details.

The Python UTF-8 Mode ignores the and forces the usage of the UTF-8 encoding

• Use UTF-8 as the

• returns

  >>> import os
  >>> statinfo = os.stat['somefile.txt']
  >>> statinfo
  os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
  st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
  st_mtime=1297230027, st_ctime=1297230027]
  >>> statinfo.st_size
  264
  

  8

• returns

  >>> import os
  >>> statinfo = os.stat['somefile.txt']
  >>> statinfo
  os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
  st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
  st_mtime=1297230027, st_ctime=1297230027]
  >>> statinfo.st_size
  264
  

  8 [the do_setlocale argument has no effect]

• , , and all use UTF-8 as their text encoding, with the

  os.stat in os.supports_dir_fd
  

  4 being enabled for and [ continues to use

  os.stat in os.supports_dir_fd
  

  8 as it does in the default locale-aware mode]

• On Unix, returns

  >>> import os
  >>> statinfo = os.stat['somefile.txt']
  >>> statinfo
  os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
  st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
  st_mtime=1297230027, st_ctime=1297230027]
  >>> statinfo.st_size
  264
  

  8 rather than the device encoding

Note that the standard stream settings in UTF-8 mode can be overridden by [just as they can be in the default locale-aware mode]

As a consequence of the changes in those lower level APIs, other higher level APIs also exhibit different default behaviours

• Command line arguments, environment variables and filenames are decoded to text using the UTF-8 encoding

• and use the UTF-8 encoding

• , , and use the UTF-8 encoding by default. However, they still use the strict error handler by default so that attempting to open a binary file in text mode is likely to raise an exception rather than producing nonsense data

The is enabled if the LC_CTYPE locale is

os.access in os.supports_effective_ids

os.access in os.supports_effective_ids

>>> import os
>>> statinfo = os.stat['somefile.txt']
>>> statinfo
os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027]
>>> statinfo.st_size
264

It can be enabled or disabled using the command line option and the environment variable

Nếu biến môi trường hoàn toàn không được đặt, thì trình thông dịch sẽ mặc định sử dụng cài đặt ngôn ngữ hiện tại, trừ khi ngôn ngữ hiện tại được xác định là ngôn ngữ dựa trên ASCII kế thừa [như được mô tả cho ] và tính năng cưỡng chế ngôn ngữ bị vô hiệu hóa hoặc không thành công. In such legacy locales, the interpreter will default to enabling UTF-8 mode unless explicitly instructed not to do so

The Python UTF-8 Mode can only be enabled at the Python startup. Its value can be read from

See also the and the

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Python 3. 15 will make default

Process Parameters

These functions and data items provide information and operate on the current process and user

Return the filename corresponding to the controlling terminal of the process

Unix, not Emscripten, not WASI

A object where keys and values are strings that represent the process environment. For example,

os.chdir in os.supports_fd

os.chdir in os.supports_fd

This mapping is captured the first time the module is imported, typically during Python startup as part of processing

os.chdir in os.supports_fd

This mapping may be used to modify the environment as well as query the environment. will be called automatically when the mapping is modified

On Unix, keys and values use and

os.stat in os.supports_follow_symlinks

Ghi chú

Calling directly does not change , so it’s better to modify

Ghi chú

On some platforms, including FreeBSD and macOS, setting

os.stat in os.supports_follow_symlinks

os.stat in os.supports_follow_symlinks

You can delete items in this mapping to unset environment variables. will be called automatically when an item is deleted from , and when one of the

import os
from os.path import join, getsize
for root, dirs, files in os.walk['python/Lib/email']:
    print[root, "consumes", end=" "]
    print[sum[getsize[join[root, name]] for name in files], end=" "]
    print["bytes in", len[files], "non-directory files"]
    if 'CVS' in dirs:
        dirs.remove['CVS']  # don't visit CVS directories

import os
from os.path import join, getsize
for root, dirs, files in os.walk['python/Lib/email']:
    print[root, "consumes", end=" "]
    print[sum[getsize[join[root, name]] for name in files], end=" "]
    print["bytes in", len[files], "non-directory files"]
    if 'CVS' in dirs:
        dirs.remove['CVS']  # don't visit CVS directories

Changed in version 3. 9. Updated to support PEP 584’s merge [

import os
from os.path import join, getsize
for root, dirs, files in os.walk['python/Lib/email']:
    print[root, "consumes", end=" "]
    print[sum[getsize[join[root, name]] for name in files], end=" "]
    print["bytes in", len[files], "non-directory files"]
    if 'CVS' in dirs:
        dirs.remove['CVS']  # don't visit CVS directories

import os
from os.path import join, getsize
for root, dirs, files in os.walk['python/Lib/email']:
    print[root, "consumes", end=" "]
    print[sum[getsize[join[root, name]] for name in files], end=" "]
    print["bytes in", len[files], "non-directory files"]
    if 'CVS' in dirs:
        dirs.remove['CVS']  # don't visit CVS directories

Bytes version of . a object where both keys and values are objects representing the process environment. and are synchronized [modifying updates , and vice versa]

is only available if is

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

New in version 3. 2

Changed in version 3. 9. Updated to support PEP 584’s merge [

import os
from os.path import join, getsize
for root, dirs, files in os.walk['python/Lib/email']:
    print[root, "consumes", end=" "]
    print[sum[getsize[join[root, name]] for name in files], end=" "]
    print["bytes in", len[files], "non-directory files"]
    if 'CVS' in dirs:
        dirs.remove['CVS']  # don't visit CVS directories

import os
from os.path import join, getsize
for root, dirs, files in os.walk['python/Lib/email']:
    print[root, "consumes", end=" "]
    print[sum[getsize[join[root, name]] for name in files], end=" "]
    print["bytes in", len[files], "non-directory files"]
    if 'CVS' in dirs:
        dirs.remove['CVS']  # don't visit CVS directories

These functions are described in

Encode filename to the ; return unchanged

is the reverse function

New in version 3. 2

Changed in version 3. 6. Support added to accept objects implementing the interface.

Decode the filename from the ; return unchanged

is the reverse function

New in version 3. 2

Changed in version 3. 6. Support added to accept objects implementing the interface.

Return the file system representation of the path

If or is passed in, it is returned unchanged. Otherwise is called and its value is returned as long as it is a or object. In all other cases, is raised

New in version 3. 6

An for objects representing a file system path, e. g.

New in version 3. 6

Return the file system path representation of the object

The method should only return a or object, with the preference being for

Return the value of the environment variable key as a string if it exists, or default if it doesn’t. key is a string. Note that since uses , the mapping of is similarly also captured on import, and the function may not reflect future environment changes

On Unix, keys and values are decoded with and

os.stat in os.supports_follow_symlinks

Unix, Windows

Return the value of the environment variable key as bytes if it exists, or default if it doesn’t. key must be bytes. Note that since uses , the mapping of is similarly also captured on import, and the function may not reflect future environment changes

is only available if is

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Unix

New in version 3. 2

Trả về danh sách các thư mục sẽ được tìm kiếm cho một tệp thực thi được đặt tên, tương tự như trình bao, khi khởi chạy một quy trình. env, khi được chỉ định, phải là một từ điển biến môi trường để tra cứu PATH trong. Theo mặc định, khi env là

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

New in version 3. 2

Trả về id nhóm hiệu quả của quy trình hiện tại. This corresponds to the “set id” bit on the file being executed in the current process

Unix, not Emscripten, not WASI

Return the current process’s effective user id

Unix, not Emscripten, not WASI

Return the real group id of the current process

Unix

The function is a stub on Emscripten and WASI, see for more information

Return list of group ids that user belongs to. If group is not in the list, it is included; typically, group is specified as the group ID field from the password record for user, because that group ID will otherwise be potentially omitted

Unix, not Emscripten, not WASI

New in version 3. 3

Return list of supplemental group ids associated with the current process

Unix, not Emscripten, not WASI

Ghi chú

On macOS, behavior differs somewhat from other Unix platforms. If the Python interpreter was built with a deployment target of

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Return the name of the user logged in on the controlling terminal of the process. For most purposes, it is more useful to use since the latter checks the environment variables

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Unix, Windows, not Emscripten, not WASI

Return the process group id of the process with process id pid. If pid is 0, the process group id of the current process is returned

Unix, not Emscripten, not WASI

Return the id of the current process group

Unix, not Emscripten, not WASI

Return the current process id

The function is a stub on Emscripten and WASI, see for more information

Return the parent’s process id. When the parent process has exited, on Unix the id returned is the one of the init process [1], on Windows it is still the same id, which may be already reused by another process

Unix, Windows, not Emscripten, not WASI

Changed in version 3. 2. Added support for Windows.

Get program scheduling priority. The value which is one of , , or , and who is interpreted relative to which [a process identifier for , process group identifier for , and a user ID for ]. A zero value for who denotes [respectively] the calling process, the process group of the calling process, or the real user ID of the calling process

Unix, not Emscripten, not WASI

New in version 3. 3

Parameters for the and functions

Unix, not Emscripten, not WASI

New in version 3. 3

Return a tuple [ruid, euid, suid] denoting the current process’s real, effective, and saved user ids

Unix, not Emscripten, not WASI

New in version 3. 2

Return a tuple [rgid, egid, sgid] denoting the current process’s real, effective, and saved group ids

Unix, not Emscripten, not WASI

New in version 3. 2

Return the current process’s real user id

Unix

The function is a stub on Emscripten and WASI, see for more information

Gọi hệ thống initgroups[] để khởi tạo danh sách truy cập nhóm với tất cả các nhóm mà tên người dùng được chỉ định là thành viên, cộng với id nhóm được chỉ định

Unix, not Emscripten, not WASI

New in version 3. 2

Set the environment variable named key to the string value. Such changes to the environment affect subprocesses started with , or and

Assignments to items in are automatically translated into corresponding calls to ; however, calls to don’t update , so it is actually preferable to assign to items of . This also applies to and , which respectively use and in their implementations

Ghi chú

On some platforms, including FreeBSD and macOS, setting

os.stat in os.supports_follow_symlinks

os.stat in os.supports_follow_symlinks

Raises an

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Changed in version 3. 9. The function is now always available.

Set the current process’s effective group id

Unix, not Emscripten, not WASI

Set the current process’s effective user id

Unix, not Emscripten, not WASI

Set the current process’ group id

Unix, not Emscripten, not WASI

Set the list of supplemental group ids associated with the current process to groups. groups must be a sequence, and each element must be an integer identifying a group. This operation is typically available only to the superuser

Unix, not Emscripten, not WASI

Ghi chú

On macOS, the length of groups may not exceed the system-defined maximum number of effective group ids, typically 16. See the documentation for for cases where it may not return the same group list set by calling setgroups[]

Call the system call

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Unix, not Emscripten, not WASI

Call the system call

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Unix, not Emscripten, not WASI

Set program scheduling priority. The value which is one of , , or , and who is interpreted relative to which [a process identifier for , process group identifier for , and a user ID for ]. A zero value for who denotes [respectively] the calling process, the process group of the calling process, or the real user ID of the calling process. ưu tiên là một giá trị trong phạm vi -20 đến 19. The default priority is 0; lower priorities cause more favorable scheduling

Unix, not Emscripten, not WASI

New in version 3. 3

Đặt id nhóm thực và hiệu quả của quy trình hiện tại

Unix, not Emscripten, not WASI

Đặt id nhóm thực, hiệu quả và đã lưu của quy trình hiện tại

Unix, not Emscripten, not WASI

New in version 3. 2

Đặt id người dùng thực, hiệu quả và đã lưu của quy trình hiện tại

Unix, not Emscripten, not WASI

New in version 3. 2

Đặt id người dùng thực và hiệu quả của quy trình hiện tại

Unix, not Emscripten, not WASI

Gọi cuộc gọi hệ thống

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Unix, not Emscripten, not WASI

Gọi cuộc gọi hệ thống

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Unix, not Emscripten, not WASI

Đặt id người dùng của quy trình hiện tại

Unix, not Emscripten, not WASI

Trả về thông báo lỗi tương ứng với mã lỗi trong code. Trên các nền tảng mà

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

New in version 3. 2

Set the current numeric umask and return the previous umask

The function is a stub on Emscripten and WASI, see for more information

Returns information identifying the current operating system. The return value is an object with five attributes

• if os.access["myfile", os.R_OK]:
      with open["myfile"] as fp:
          return fp.read[]
  return "some default data"
  

  93 - operating system name

• if os.access["myfile", os.R_OK]:
      with open["myfile"] as fp:
          return fp.read[]
  return "some default data"
  

  94 - name of machine on network [implementation-defined]

• if os.access["myfile", os.R_OK]:
      with open["myfile"] as fp:
          return fp.read[]
  return "some default data"
  

  95 - operating system release

• if os.access["myfile", os.R_OK]:
      with open["myfile"] as fp:
          return fp.read[]
  return "some default data"
  

  96 - operating system version

• if os.access["myfile", os.R_OK]:
      with open["myfile"] as fp:
          return fp.read[]
  return "some default data"
  

  97 - hardware identifier

For backwards compatibility, this object is also iterable, behaving like a five-tuple containing

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Some systems truncate

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix

Changed in version 3. 3. Return type changed from a tuple to a tuple-like object with named attributes.

Unset [delete] the environment variable named key. Such changes to the environment affect subprocesses started with , or and

Deletion of items in is automatically translated into a corresponding call to ; however, calls to don’t update , so it is actually preferable to delete items of

Raises an

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Changed in version 3. 9. The function is now always available and is also available on Windows.

File Object Creation

These functions create new . [See also for opening file descriptors. ]

Return an open file object connected to the file descriptor fd. This is an alias of the built-in function and accepts the same arguments. The only difference is that the first argument of must always be an integer

File Descriptor Operations

These functions operate on I/O streams referenced using file descriptors

File descriptors are small integers corresponding to a file that has been opened by the current process. Ví dụ: đầu vào tiêu chuẩn thường là bộ mô tả tệp 0, đầu ra tiêu chuẩn là 1 và lỗi tiêu chuẩn là 2. Further files opened by a process will then be assigned 3, 4, 5, and so forth. The name “file descriptor” is slightly deceptive; on Unix platforms, sockets and pipes are also referenced by file descriptors

The method can be used to obtain the file descriptor associated with a when required. Note that using the file descriptor directly will bypass the file object methods, ignoring aspects such as internal buffering of data

Close file descriptor fd

Ghi chú

This function is intended for low-level I/O and must be applied to a file descriptor as returned by or . To close a “file object” returned by the built-in function or by or , use its method

Close all file descriptors from fd_low [inclusive] to fd_high [exclusive], ignoring errors. Equivalent to [but much faster than]

for fd in range[fd_low, fd_high]:
    try:
        os.close[fd]
    except OSError:
        pass

Copy count bytes from file descriptor src, starting from offset offset_src, to file descriptor dst, starting from offset offset_dst. If offset_src is None, then src is read from the current position; respectively for offset_dst. The files pointed by src and dst must reside in the same filesystem, otherwise an is raised with set to

This copy is done without the additional cost of transferring data from the kernel to user space and then back into the kernel. Additionally, some filesystems could implement extra optimizations. The copy is done as if both files are opened as binary

The return value is the amount of bytes copied. This could be less than the amount requested

Linux >= 4. 5 with glibc >= 2. 27

New in version 3. 8

Return a string describing the encoding of the device associated with fd if it is connected to a terminal; else return

Trên Unix, nếu được bật, hãy trả về

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Changed in version 3. 10. On Unix, the function now implements the Python UTF-8 Mode.

Return a duplicate of file descriptor fd. The new file descriptor is

On Windows, when duplicating a standard stream [0. stdin, 1. stdout, 2. stderr], the new file descriptor is

not WASI

Changed in version 3. 4. The new file descriptor is now non-inheritable.

Duplicate file descriptor fd to fd2, closing the latter first if necessary. Return fd2. Bộ mô tả tệp mới theo mặc định hoặc không thể kế thừa nếu có thể kế thừa là

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

not WASI

Changed in version 3. 4. Add the optional inheritable parameter.

Changed in version 3. 7. Return fd2 on success. Previously,

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Change the mode of the file given by fd to the numeric mode. See the docs for for possible values of mode. As of Python 3. 3, this is equivalent to

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Raises an

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix

The function is limited on Emscripten and WASI, see for more information

Change the owner and group id of the file given by fd to the numeric uid and gid. To leave one of the ids unchanged, set it to -1. See . As of Python 3. 3, this is equivalent to

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Raises an

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix

The function is limited on Emscripten and WASI, see for more information

Force write of file with filedescriptor fd to disk. Does not force update of metadata

Unix

Ghi chú

This function is not available on MacOS

Return system configuration information relevant to an open file. name specifies the configuration value to retrieve; it may be a string which is the name of a defined system value; these names are specified in a number of standards [POSIX. 1, Unix 95, Unix 98, and others]. Some platforms define additional names as well. The names known to the host operating system are given in the

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

If name is a string and is not known, is raised. If a specific value for name is not supported by the host system, even if it is included in

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

As of Python 3. 3, this is equivalent to

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix

Get the status of the file descriptor fd. Return a object

As of Python 3. 3, this is equivalent to

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Xem thêm

The function

Return information about the filesystem containing the file associated with file descriptor fd, like . As of Python 3. 3, this is equivalent to

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix

Force write of file with filedescriptor fd to disk. On Unix, this calls the native

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

If you’re starting with a buffered Python f, first do

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix, Windows

Truncate the file corresponding to file descriptor fd, so that it is at most length bytes in size. As of Python 3. 3, this is equivalent to

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Raises an

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix, Windows

Changed in version 3. 5. Added support for Windows

Get the blocking mode of the file descriptor.

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

See also and

Unix

The function is limited on Emscripten and WASI, see for more information

New in version 3. 5

Return

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Apply, test or remove a POSIX lock on an open file descriptor. fd is an open file descriptor. cmd specifies the command to use - one of , , or . len specifies the section of the file to lock

Raises an

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix

New in version 3. 3

Flags that specify what action will take

Unix

New in version 3. 3

Prepare the tty of which fd is a file descriptor for a new login session. Make the calling process a session leader; make the tty the controlling tty, the stdin, the stdout, and the stderr of the calling process; close fd

Unix, not Emscripten, not WASI

New in version 3. 11

Set the current position of file descriptor fd to position pos, modified by how. hoặc

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Parameters to the function. Giá trị của chúng lần lượt là 0, 1 và 2

New in version 3. 3. Some operating systems could support additional values, like

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Open the file path and set various flags according to flags and possibly its mode according to mode. When computing mode, the current umask value is first masked out. Return the file descriptor for the newly opened file. The new file descriptor is

For a description of the flag and mode values, see the C run-time documentation; flag constants [like and ] are defined in the module. In particular, on Windows adding is needed to open files in binary mode

This function can support with the dir_fd parameter

Raises an

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Changed in version 3. 4. The new file descriptor is now non-inheritable.

Ghi chú

This function is intended for low-level I/O. For normal usage, use the built-in function , which returns a with

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

New in version 3. 3. The dir_fd argument.

Changed in version 3. 5. If the system call is interrupted and the signal handler does not raise an exception, the function now retries the system call instead of raising an exception [see PEP 475 for the rationale].

Changed in version 3. 6. Accepts a .

The following constants are options for the flags parameter to the function. They can be combined using the bitwise OR operator

import os
from os.path import join, getsize
for root, dirs, files in os.walk['python/Lib/email']:
    print[root, "consumes", end=" "]
    print[sum[getsize[join[root, name]] for name in files], end=" "]
    print["bytes in", len[files], "non-directory files"]
    if 'CVS' in dirs:
        dirs.remove['CVS']  # don't visit CVS directories

The above constants are available on Unix and Windows

The above constants are only available on Unix

Changed in version 3. 3. Add constant.

The above constants are only available on Windows

The above constants are only available on macOS

Changed in version 3. 10. Add , , and constants.

The above constants are extensions and not present if they are not defined by the C library

Changed in version 3. 4. Add on systems that support it. Add , only available on Linux Kernel 3. 11 or newer.

Open a new pseudo-terminal pair. Return a pair of file descriptors

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

Unix, not Emscripten, not WASI

Changed in version 3. 4. The new file descriptors are now non-inheritable.

Create a pipe. Return a pair of file descriptors

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

Unix, Windows

Changed in version 3. 4. The new file descriptors are now non-inheritable.

Create a pipe with flags set atomically. cờ có thể được xây dựng bằng ORing với nhau một hoặc nhiều giá trị này. , . Trả về một cặp mô tả tệp

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

Unix, not Emscripten, not WASI

New in version 3. 3

Đảm bảo phân bổ đủ dung lượng đĩa cho tệp được chỉ định bởi fd bắt đầu từ offset và tiếp tục cho len byte

Unix, không phải Emscripten

New in version 3. 3

Thông báo ý định truy cập dữ liệu theo một mẫu cụ thể, do đó cho phép hạt nhân thực hiện tối ưu hóa. Lời khuyên áp dụng cho vùng của tệp được chỉ định bởi fd bắt đầu từ offset và tiếp tục cho len byte. lời khuyên là một trong , , , , hoặc

Unix

New in version 3. 3

Flags that can be used in advice in that specify the access pattern that is likely to be used

Unix

New in version 3. 3

Read at most n bytes from file descriptor fd at a position of offset, leaving the file offset unchanged

Return a bytestring containing the bytes read. If the end of the file referred to by fd has been reached, an empty bytes object is returned

Unix

New in version 3. 3

Read from a file descriptor fd at a position of offset into mutable buffers, leaving the file offset unchanged. Transfer data into each buffer until it is full and then move on to the next buffer in the sequence to hold the rest of the data

The flags argument contains a bitwise OR of zero or more of the following flags

Return the total number of bytes actually read which can be less than the total capacity of all the objects

The operating system may set a limit [ value

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

Combine the functionality of and

Linux >= 2. 6. 30, FreeBSD >= 6. 0, OpenBSD >= 2. 7, AIX >= 7. 1

Using flags requires Linux >= 4. 6

New in version 3. 7

Đừng đợi dữ liệu không có sẵn ngay lập tức. Nếu cờ này được chỉ định, lệnh gọi hệ thống sẽ trả về ngay lập tức nếu nó phải đọc dữ liệu từ bộ lưu trữ dự phòng hoặc chờ khóa

If some data was successfully read, it will return the number of bytes read. If no bytes were read, it will return

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

Linux >= 4. 14

New in version 3. 7

High priority read/write. Cho phép các hệ thống tệp dựa trên khối sử dụng tính năng bỏ phiếu của thiết bị, mang lại độ trễ thấp hơn nhưng có thể sử dụng các tài nguyên bổ sung

Currently, on Linux, this feature is usable only on a file descriptor opened using the flag

Linux >= 4. 6

New in version 3. 7

Write the bytestring in str to file descriptor fd at position of offset, leaving the file offset unchanged

Return the number of bytes actually written

Unix

New in version 3. 3

Write the buffers contents to file descriptor fd at a offset offset, leaving the file offset unchanged. buffers must be a sequence of . Buffers are processed in array order. Entire contents of the first buffer is written before proceeding to the second, and so on

The flags argument contains a bitwise OR of zero or more of the following flags

Return the total number of bytes actually written

The operating system may set a limit [ value

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

Combine the functionality of and

Linux >= 2. 6. 30, FreeBSD >= 6. 0, OpenBSD >= 2. 7, AIX >= 7. 1

Using flags requires Linux >= 4. 6

New in version 3. 7

Provide a per-write equivalent of the flag. This flag effect applies only to the data range written by the system call

Linux >= 4. 7

New in version 3. 7

Provide a per-write equivalent of the flag. This flag effect applies only to the data range written by the system call

Linux >= 4. 7

New in version 3. 7

Provide a per-write equivalent of the flag. This flag is meaningful only for , and its effect applies only to the data range written by the system call. The offset argument does not affect the write operation; the data is always appended to the end of the file. However, if the offset argument is

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

Linux >= 4. 16

New in version 3. 10

Read at most n bytes from file descriptor fd

Return a bytestring containing the bytes read. If the end of the file referred to by fd has been reached, an empty bytes object is returned

Ghi chú

This function is intended for low-level I/O and must be applied to a file descriptor as returned by or . To read a “file object” returned by the built-in function or by or , or , use its

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

Changed in version 3. 5. If the system call is interrupted and the signal handler does not raise an exception, the function now retries the system call instead of raising an exception [see PEP 475 for the rationale].

Copy count bytes from file descriptor in_fd to file descriptor out_fd starting at offset. Return the number of bytes sent. When EOF is reached return

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

The first function notation is supported by all platforms that define

On Linux, if offset is given as

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

The second case may be used on macOS and FreeBSD where headers and trailers are arbitrary sequences of buffers that are written before and after the data from in_fd is written. It returns the same as the first case

On macOS and FreeBSD, a value of

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

All platforms support sockets as out_fd file descriptor, and some platforms allow other types [e. g. regular file, pipe] as well

Cross-platform applications should not use headers, trailers and flags arguments

Unix, not Emscripten, not WASI

Ghi chú

For a higher-level wrapper of , see

New in version 3. 3

Changed in version 3. 9. Parameters out and in was renamed to out_fd and in_fd.

Set the blocking mode of the specified file descriptor. Set the flag if blocking is

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

See also and

Unix

The function is limited on Emscripten and WASI, see for more information

New in version 3. 5

Parameters to the function, if the implementation supports them

Unix, not Emscripten, not WASI

New in version 3. 3

Parameter to the function, if the implementation supports it. The data won’t be cached in the virtual memory and will be freed afterwards

Unix, not Emscripten, not WASI

New in version 3. 11

Transfer count bytes from file descriptor src, starting from offset offset_src, to file descriptor dst, starting from offset offset_dst. At least one of the file descriptors must refer to a pipe. If offset_src is None, then src is read from the current position; respectively for offset_dst. The offset associated to the file descriptor that refers to a pipe must be

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

This copy is done without the additional cost of transferring data from the kernel to user space and then back into the kernel. Additionally, some filesystems could implement extra optimizations. The copy is done as if both files are opened as binary

Upon successful completion, returns the number of bytes spliced to or from the pipe. A return value of 0 means end of input. If src refers to a pipe, then this means that there was no data to transfer, and it would not make sense to block because there are no writers connected to the write end of the pipe

Linux >= 2. 6. 17 with glibc >= 2. 5

New in version 3. 10

New in version 3. 10

Read from a file descriptor fd into a number of mutable buffers. Transfer data into each buffer until it is full and then move on to the next buffer in the sequence to hold the rest of the data

Return the total number of bytes actually read which can be less than the total capacity of all the objects

The operating system may set a limit [ value

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

Unix

New in version 3. 3

Return the process group associated with the terminal given by fd [an open file descriptor as returned by ]

Unix, not WASI

Set the process group associated with the terminal given by fd [an open file descriptor as returned by ] to pg

Unix, not WASI

Return a string which specifies the terminal device associated with file descriptor fd. If fd is not associated with a terminal device, an exception is raised

Unix

Write the bytestring in str to file descriptor fd

Return the number of bytes actually written

Ghi chú

This function is intended for low-level I/O and must be applied to a file descriptor as returned by or . To write a “file object” returned by the built-in function or by or , or or , use its

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

Changed in version 3. 5. If the system call is interrupted and the signal handler does not raise an exception, the function now retries the system call instead of raising an exception [see PEP 475 for the rationale].

Write the contents of buffers to file descriptor fd. bộ đệm phải là một chuỗi các. Buffers are processed in array order. Entire contents of the first buffer is written before proceeding to the second, and so on

Returns the total number of bytes actually written

The operating system may set a limit [ value

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

Unix

New in version 3. 3

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

with os.scandir[path] as it:
    for entry in it:
        if not entry.name.startswith['.'] and entry.is_file[]:
            print[entry.name]

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Files and Directories

On some Unix platforms, many of these functions support one or more of these features

• specifying a file descriptor. Normally the path argument provided to functions in the module must be a string specifying a file path. However, some functions now alternatively accept an open file descriptor for their path argument. The function will then operate on the file referred to by the descriptor. [For POSIX systems, Python will call the variant of the function prefixed with

  >>> import os
  >>> statinfo = os.stat['somefile.txt']
  >>> statinfo
  os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
  st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
  st_mtime=1297230027, st_ctime=1297230027]
  >>> statinfo.st_size
  264
  

  04 [e. g. call

  >>> import os
  >>> statinfo = os.stat['somefile.txt']
  >>> statinfo
  os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
  st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
  st_mtime=1297230027, st_ctime=1297230027]
  >>> statinfo.st_size
  264
  

  05 instead of

  >>> import os
  >>> statinfo = os.stat['somefile.txt']
  >>> statinfo
  os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
  st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
  st_mtime=1297230027, st_ctime=1297230027]
  >>> statinfo.st_size
  264
  

  06]. ]

  You can check whether or not path can be specified as a file descriptor for a particular function on your platform using . If this functionality is unavailable, using it will raise a

  If the function also supports dir_fd or follow_symlinks arguments, it’s an error to specify one of those when supplying path as a file descriptor

• paths relative to directory descriptors. If dir_fd is not

  if os.access["myfile", os.R_OK]:
      with open["myfile"] as fp:
          return fp.read[]
  return "some default data"
  

  35, it should be a file descriptor referring to a directory, and the path to operate on should be relative; path will then be relative to that directory. If the path is absolute, dir_fd is ignored. [For POSIX systems, Python will call the variant of the function with an

  >>> import os
  >>> statinfo = os.stat['somefile.txt']
  >>> statinfo
  os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
  st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
  st_mtime=1297230027, st_ctime=1297230027]
  >>> statinfo.st_size
  264
  

  10 suffix and possibly prefixed with

  >>> import os
  >>> statinfo = os.stat['somefile.txt']
  >>> statinfo
  os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
  st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
  st_mtime=1297230027, st_ctime=1297230027]
  >>> statinfo.st_size
  264
  

  04 [e. g. call

  >>> import os
  >>> statinfo = os.stat['somefile.txt']
  >>> statinfo
  os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
  st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
  st_mtime=1297230027, st_ctime=1297230027]
  >>> statinfo.st_size
  264
  

  12 instead of

  >>> import os
  >>> statinfo = os.stat['somefile.txt']
  >>> statinfo
  os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
  st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
  st_mtime=1297230027, st_ctime=1297230027]
  >>> statinfo.st_size
  264
  

  13]

  You can check whether or not dir_fd is supported for a particular function on your platform using . If it’s unavailable, using it will raise a

• not following symlinks. Nếu follow_symlinks là

  if os.access["myfile", os.R_OK]:
      with open["myfile"] as fp:
          return fp.read[]
  return "some default data"
  

  92 và phần tử cuối cùng của đường dẫn hoạt động trên đó là một liên kết tượng trưng, ​​thì hàm sẽ hoạt động trên chính liên kết tượng trưng đó chứ không phải tệp được chỉ ra bởi liên kết. [For POSIX systems, Python will call the

  >>> import os
  >>> statinfo = os.stat['somefile.txt']
  >>> statinfo
  os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
  st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
  st_mtime=1297230027, st_ctime=1297230027]
  >>> statinfo.st_size
  264
  

  17 variant of the function. ]

  You can check whether or not follow_symlinks is supported for a particular function on your platform using . Nếu nó không có sẵn, sử dụng nó sẽ tăng

Use the real uid/gid to test for access to path. Lưu ý rằng hầu hết các hoạt động sẽ sử dụng uid/gid hiệu quả, do đó, quy trình này có thể được sử dụng trong môi trường suid/sgid để kiểm tra xem người dùng đang gọi có quyền truy cập được chỉ định vào đường dẫn hay không. mode should be to test the existence of path, or it can be the inclusive OR of one or more of , , and to test permissions. Return if access is allowed, if not. See the Unix man page access[2] for more information

This function can support specifying and

Nếu effect_ids là

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Ghi chú

Using to check if a user is authorized to e. g. open a file before actually doing so using creates a security hole, because the user might exploit the short time interval between checking and opening the file to manipulate it. It’s preferable to use techniques. For example

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

is better written as

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Ghi chú

I/O operations may fail even when indicates that they would succeed, particularly for operations on network filesystems which may have permissions semantics beyond the usual POSIX permission-bit model

Changed in version 3. 3. Added the dir_fd, effective_ids, and follow_symlinks parameters.

Changed in version 3. 6. Accepts a .

Values to pass as the mode parameter of to test the existence, readability, writability and executability of path, respectively

Change the current working directory to path

This function can support . The descriptor must refer to an opened directory, not an open file

This function can raise and subclasses such as , , and

Raises an

>>> import os
>>> statinfo = os.stat['somefile.txt']
>>> statinfo
os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027]
>>> statinfo.st_size
264

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

New in version 3. 3. Added support for specifying path as a file descriptor on some platforms.

Changed in version 3. 6. Accepts a .

Set the flags of path to the numeric flags. flags may take a combination [bitwise OR] of the following values [as defined in the module]

This function can support

Raises an

>>> import os
>>> statinfo = os.stat['somefile.txt']
>>> statinfo
os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027]
>>> statinfo.st_size
264

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix, not Emscripten, not WASI

New in version 3. 3. The follow_symlinks argument.

Changed in version 3. 6. Accepts a .

Change the mode of path to the numeric mode. mode may take one of the following values [as defined in the module] or bitwise ORed combinations of them

This function can support , and

Ghi chú

Although Windows supports , you can only set the file’s read-only flag with it [via the

>>> import os
>>> statinfo = os.stat['somefile.txt']
>>> statinfo
os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027]
>>> statinfo.st_size
264

>>> import os
>>> statinfo = os.stat['somefile.txt']
>>> statinfo
os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027]
>>> statinfo.st_size
264

The function is limited on Emscripten and WASI, see for more information

Raises an

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

New in version 3. 3. Added support for specifying path as an open file descriptor, and the dir_fd and follow_symlinks arguments.

Changed in version 3. 6. Accepts a .

Change the owner and group id of path to the numeric uid and gid. Để giữ nguyên một trong các id, hãy đặt nó thành -1

This function can support , and

See for a higher-level function that accepts names in addition to numeric ids

Raises an

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix

The function is limited on Emscripten and WASI, see for more information

New in version 3. 3. Added support for specifying path as an open file descriptor, and the dir_fd and follow_symlinks arguments.

Changed in version 3. 6. Supports a .

Change the root directory of the current process to path

Unix, not Emscripten, not WASI

Changed in version 3. 6. Accepts a .

Change the current working directory to the directory represented by the file descriptor fd. The descriptor must refer to an opened directory, not an open file. As of Python 3. 3, this is equivalent to

>>> import os
>>> statinfo = os.stat['somefile.txt']
>>> statinfo
os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027]
>>> statinfo.st_size
264

Raises an

>>> import os
>>> statinfo = os.stat['somefile.txt']
>>> statinfo
os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027]
>>> statinfo.st_size
264

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix

Return a string representing the current working directory

Return a bytestring representing the current working directory

Changed in version 3. 8. The function now uses the UTF-8 encoding on Windows, rather than the ANSI code page. see PEP 529 for the rationale. The function is no longer deprecated on Windows.

Set the flags of path to the numeric flags, like , but do not follow symbolic links. As of Python 3. 3, this is equivalent to

>>> import os
>>> statinfo = os.stat['somefile.txt']
>>> statinfo
os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027]
>>> statinfo.st_size
264

Raises an

>>> import os
>>> statinfo = os.stat['somefile.txt']
>>> statinfo
os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027]
>>> statinfo.st_size
264

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix, not Emscripten, not WASI

Changed in version 3. 6. Accepts a .

Change the mode of path to the numeric mode. If path is a symlink, this affects the symlink rather than the target. See the docs for for possible values of mode. As of Python 3. 3, this is equivalent to

>>> import os
>>> statinfo = os.stat['somefile.txt']
>>> statinfo
os.stat_result[st_mode=33188, st_ino=7876932, st_dev=234881026,
st_nlink=1, st_uid=501, st_gid=501, st_size=264, st_atime=1297230295,
st_mtime=1297230027, st_ctime=1297230027]
>>> statinfo.st_size
264

Raises an

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix

Changed in version 3. 6. Accepts a .

Change the owner and group id of path to the numeric uid and gid. This function will not follow symbolic links. As of Python 3. 3, this is equivalent to

os.stat in os.supports_dir_fd

Raises an

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Unix

Changed in version 3. 6. Accepts a .

Create a hard link pointing to src named dst

This function can support specifying src_dir_fd and/or dst_dir_fd to supply , and

Raises an

os.stat in os.supports_dir_fd

os.stat in os.supports_dir_fd

os.stat in os.supports_dir_fd

os.stat in os.supports_dir_fd

os.stat in os.supports_dir_fd

Unix, Windows

Changed in version 3. 2. Added Windows support.

New in version 3. 3. Added the src_dir_fd, dst_dir_fd, and follow_symlinks arguments.

Changed in version 3. 6. Accepts a for src and dst.

Trả về danh sách chứa tên của các mục trong thư mục được cung cấp bởi đường dẫn. The list is in arbitrary order, and does not include the special entries

os.stat in os.supports_dir_fd

os.stat in os.supports_dir_fd

con đường có thể là một. If path is of type

import os
from os.path import join, getsize
for root, dirs, files in os.walk['python/Lib/email']:
    print[root, "consumes", end=" "]
    print[sum[getsize[join[root, name]] for name in files], end=" "]
    print["bytes in", len[files], "non-directory files"]
    if 'CVS' in dirs:
        dirs.remove['CVS']  # don't visit CVS directories

import os
from os.path import join, getsize
for root, dirs, files in os.walk['python/Lib/email']:
    print[root, "consumes", end=" "]
    print[sum[getsize[join[root, name]] for name in files], end=" "]
    print["bytes in", len[files], "non-directory files"]
    if 'CVS' in dirs:
        dirs.remove['CVS']  # don't visit CVS directories

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

This function can also support ; the file descriptor must refer to a directory

Đưa ra một

os.stat in os.supports_dir_fd

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

Ghi chú

Để mã hóa tên tệp

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

import os
from os.path import join, getsize
for root, dirs, files in os.walk['python/Lib/email']:
    print[root, "consumes", end=" "]
    print[sum[getsize[join[root, name]] for name in files], end=" "]
    print["bytes in", len[files], "non-directory files"]
    if 'CVS' in dirs:
        dirs.remove['CVS']  # don't visit CVS directories

Xem thêm

The function returns directory entries along with file attribute information, giving better performance for many common use cases

Changed in version 3. 2. The path parameter became optional.

New in version 3. 3. Added support for specifying path as an open file descriptor.

Changed in version 3. 6. Accepts a .

Perform the equivalent of an

os.stat in os.supports_dir_fd

On platforms that do not support symbolic links, this is an alias for

As of Python 3. 3, this is equivalent to

os.stat in os.supports_dir_fd

This function can also support

Xem thêm

The function

Changed in version 3. 2. Added support for Windows 6. 0 [Vista] symbolic links.

Changed in version 3. 3. Added the dir_fd parameter.

Changed in version 3. 6. Accepts a .

Changed in version 3. 8. On Windows, now opens reparse points that represent another path [name surrogates], including symbolic links and directory junctions. Other kinds of reparse points are resolved by the operating system as for .

Create a directory named path with numeric mode mode

If the directory already exists, is raised. If a parent directory in the path does not exist, is raised

On some systems, mode is ignored. Where it is used, the current umask value is first masked out. If bits other than the last 9 [i. e. the last 3 digits of the octal representation of the mode] are set, their meaning is platform-dependent. On some platforms, they are ignored and you should call explicitly to set them

This function can also support

It is also possible to create temporary directories; see the module’s function

Raises an

os.stat in os.supports_dir_fd

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

New in version 3. 3. The dir_fd argument.

Changed in version 3. 6. Accepts a .

Recursive directory creation function. Like , but makes all intermediate-level directories needed to contain the leaf directory

The mode parameter is passed to for creating the leaf directory; see for how it is interpreted. To set the file permission bits of any newly created parent directories you can set the umask before invoking . The file permission bits of existing parent directories are not changed

If exist_ok is

if os.access["myfile", os.R_OK]:
    with open["myfile"] as fp:
        return fp.read[]
return "some default data"

Ghi chú

sẽ trở nên bối rối nếu các phần tử đường dẫn cần tạo bao gồm [ví dụ:. “. ” on UNIX systems]

This function handles UNC paths correctly

Raises an

os.stat in os.supports_dir_fd

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]

try:
    fp = open["myfile"]
except PermissionError:
    return "some default data"
else:
    with fp:
        return fp.read[]