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:mod:`struct` --- Interpret bytes as packed binary data
Merged revisions 74821,74828-74831,74833,74835 via svnmerge from svn+ssh://svn.python.org/python/branches/py3k ................ r74821 | georg.brandl | 2009-09-16 11:42:19 +0200 (Mi, 16 Sep 2009) | 1 line #6885: run python 3 as python3. ................ r74828 | georg.brandl | 2009-09-16 16:23:20 +0200 (Mi, 16 Sep 2009) | 1 line Use true booleans. ................ r74829 | georg.brandl | 2009-09-16 16:24:29 +0200 (Mi, 16 Sep 2009) | 1 line Small PEP8 correction. ................ r74830 | georg.brandl | 2009-09-16 16:36:22 +0200 (Mi, 16 Sep 2009) | 1 line Use true booleans. ................ r74831 | georg.brandl | 2009-09-16 17:54:04 +0200 (Mi, 16 Sep 2009) | 1 line Use true booleans and PEP8 for argdefaults. ................ r74833 | georg.brandl | 2009-09-16 17:58:14 +0200 (Mi, 16 Sep 2009) | 1 line Last round of adapting style of documenting argument default values. ................ r74835 | georg.brandl | 2009-09-16 18:00:31 +0200 (Mi, 16 Sep 2009) | 33 lines Merged revisions 74817-74820,74822-74824 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r74817 | georg.brandl | 2009-09-16 11:05:11 +0200 (Mi, 16 Sep 2009) | 1 line Make deprecation notices as visible as warnings are right now. ........ r74818 | georg.brandl | 2009-09-16 11:23:04 +0200 (Mi, 16 Sep 2009) | 1 line #6880: add reference to classes section in exceptions section, which comes earlier. ........ r74819 | georg.brandl | 2009-09-16 11:24:57 +0200 (Mi, 16 Sep 2009) | 1 line #6876: fix base class constructor invocation in example. ........ r74820 | georg.brandl | 2009-09-16 11:30:48 +0200 (Mi, 16 Sep 2009) | 1 line #6891: comment out dead link to Unicode article. ........ r74822 | georg.brandl | 2009-09-16 12:12:06 +0200 (Mi, 16 Sep 2009) | 1 line #5621: refactor description of how class/instance attributes interact on a.x=a.x+1 or augassign. ........ r74823 | georg.brandl | 2009-09-16 15:06:22 +0200 (Mi, 16 Sep 2009) | 1 line Remove strange trailing commas. ........ r74824 | georg.brandl | 2009-09-16 15:11:06 +0200 (Mi, 16 Sep 2009) | 1 line #6892: fix optparse example involving help option. ........ ................
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=======================================================
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.. module:: struct
:synopsis: Interpret bytes as packed binary data.
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.. index::
pair: C; structures
triple: packing; binary; data
This module performs conversions between Python values and C structs represented
as Python :class:`bytes` objects. This can be used in handling binary data
stored in files or from network connections, among other sources. It uses
:ref:`struct-format-strings` as compact descriptions of the layout of the C
structs and the intended conversion to/from Python values.
.. note::
By default, the result of packing a given C struct includes pad bytes in
order to maintain proper alignment for the C types involved; similarly,
alignment is taken into account when unpacking. This behavior is chosen so
that the bytes of a packed struct correspond exactly to the layout in memory
of the corresponding C struct. To handle platform-independent data formats
or omit implicit pad bytes, use `standard` size and alignment instead of
`native` size and alignment: see :ref:`struct-alignment` for details.
Functions and Exceptions
------------------------
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The module defines the following exception and functions:
.. exception:: error
Exception raised on various occasions; argument is a string describing what
is wrong.
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.. function:: pack(fmt, v1, v2, ...)
Return a bytes object containing the values *v1*, *v2*, ... packed according
to the format string *fmt*. The arguments must match the values required by
the format exactly.
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.. function:: pack_into(fmt, buffer, offset, v1, v2, ...)
Pack the values *v1*, *v2*, ... according to the format string *fmt* and
write the packed bytes into the writable buffer *buffer* starting at
position *offset*. Note that *offset* is a required argument.
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.. function:: unpack(fmt, buffer)
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Unpack from the buffer *buffer* (presumably packed by ``pack(fmt, ...)``)
according to the format string *fmt*. The result is a tuple even if it
contains exactly one item. The buffer must contain exactly the amount of
data required by the format (``len(bytes)`` must equal ``calcsize(fmt)``).
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Merged revisions 74821,74828-74831,74833,74835 via svnmerge from svn+ssh://svn.python.org/python/branches/py3k ................ r74821 | georg.brandl | 2009-09-16 11:42:19 +0200 (Mi, 16 Sep 2009) | 1 line #6885: run python 3 as python3. ................ r74828 | georg.brandl | 2009-09-16 16:23:20 +0200 (Mi, 16 Sep 2009) | 1 line Use true booleans. ................ r74829 | georg.brandl | 2009-09-16 16:24:29 +0200 (Mi, 16 Sep 2009) | 1 line Small PEP8 correction. ................ r74830 | georg.brandl | 2009-09-16 16:36:22 +0200 (Mi, 16 Sep 2009) | 1 line Use true booleans. ................ r74831 | georg.brandl | 2009-09-16 17:54:04 +0200 (Mi, 16 Sep 2009) | 1 line Use true booleans and PEP8 for argdefaults. ................ r74833 | georg.brandl | 2009-09-16 17:58:14 +0200 (Mi, 16 Sep 2009) | 1 line Last round of adapting style of documenting argument default values. ................ r74835 | georg.brandl | 2009-09-16 18:00:31 +0200 (Mi, 16 Sep 2009) | 33 lines Merged revisions 74817-74820,74822-74824 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r74817 | georg.brandl | 2009-09-16 11:05:11 +0200 (Mi, 16 Sep 2009) | 1 line Make deprecation notices as visible as warnings are right now. ........ r74818 | georg.brandl | 2009-09-16 11:23:04 +0200 (Mi, 16 Sep 2009) | 1 line #6880: add reference to classes section in exceptions section, which comes earlier. ........ r74819 | georg.brandl | 2009-09-16 11:24:57 +0200 (Mi, 16 Sep 2009) | 1 line #6876: fix base class constructor invocation in example. ........ r74820 | georg.brandl | 2009-09-16 11:30:48 +0200 (Mi, 16 Sep 2009) | 1 line #6891: comment out dead link to Unicode article. ........ r74822 | georg.brandl | 2009-09-16 12:12:06 +0200 (Mi, 16 Sep 2009) | 1 line #5621: refactor description of how class/instance attributes interact on a.x=a.x+1 or augassign. ........ r74823 | georg.brandl | 2009-09-16 15:06:22 +0200 (Mi, 16 Sep 2009) | 1 line Remove strange trailing commas. ........ r74824 | georg.brandl | 2009-09-16 15:11:06 +0200 (Mi, 16 Sep 2009) | 1 line #6892: fix optparse example involving help option. ........ ................
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.. function:: unpack_from(fmt, buffer, offset=0)
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Unpack from *buffer* starting at position *offset*, according to the format
string *fmt*. The result is a tuple even if it contains exactly one
item. *buffer* must contain at least the amount of data required by the
format (``len(buffer[offset:])`` must be at least ``calcsize(fmt)``).
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.. function:: calcsize(fmt)
Return the size of the struct (and hence of the bytes object produced by
``pack(fmt, ...)``) corresponding to the format string *fmt*.
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.. _struct-format-strings:
Format Strings
--------------
Format strings are the mechanism used to specify the expected layout when
packing and unpacking data. They are built up from :ref:`format-characters`,
which specify the type of data being packed/unpacked. In addition, there are
special characters for controlling the :ref:`struct-alignment`.
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.. _struct-alignment:
Byte Order, Size, and Alignment
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
By default, C types are represented in the machine's native format and byte
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order, and properly aligned by skipping pad bytes if necessary (according to the
rules used by the C compiler).
Alternatively, the first character of the format string can be used to indicate
the byte order, size and alignment of the packed data, according to the
following table:
+-----------+------------------------+----------+-----------+
| Character | Byte order | Size | Alignment |
+===========+========================+==========+===========+
| ``@`` | native | native | native |
+-----------+------------------------+----------+-----------+
| ``=`` | native | standard | none |
+-----------+------------------------+----------+-----------+
| ``<`` | little-endian | standard | none |
+-----------+------------------------+----------+-----------+
| ``>`` | big-endian | standard | none |
+-----------+------------------------+----------+-----------+
| ``!`` | network (= big-endian) | standard | none |
+-----------+------------------------+----------+-----------+
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If the first character is not one of these, ``'@'`` is assumed.
Native byte order is big-endian or little-endian, depending on the host
system. For example, Intel x86 and AMD64 (x86-64) are little-endian;
Motorola 68000 and PowerPC G5 are big-endian; ARM and Intel Itanium feature
switchable endianness (bi-endian). Use ``sys.byteorder`` to check the
endianness of your system.
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Native size and alignment are determined using the C compiler's
``sizeof`` expression. This is always combined with native byte order.
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Standard size depends only on the format character; see the table in
the :ref:`format-characters` section.
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Note the difference between ``'@'`` and ``'='``: both use native byte order, but
the size and alignment of the latter is standardized.
The form ``'!'`` is available for those poor souls who claim they can't remember
whether network byte order is big-endian or little-endian.
There is no way to indicate non-native byte order (force byte-swapping); use the
appropriate choice of ``'<'`` or ``'>'``.
Notes:
(1) Padding is only automatically added between successive structure members.
No padding is added at the beginning or the end of the encoded struct.
(2) No padding is added when using non-native size and alignment, e.g.
with '<', '>', '=', and '!'.
(3) To align the end of a structure to the alignment requirement of a
particular type, end the format with the code for that type with a repeat
count of zero. See :ref:`struct-examples`.
.. _format-characters:
Format Characters
^^^^^^^^^^^^^^^^^
Format characters have the following meaning; the conversion between C and
Python values should be obvious given their types. The 'Standard size' column
refers to the size of the packed value in bytes when using standard size; that
is, when the format string starts with one of ``'<'``, ``'>'``, ``'!'`` or
``'='``. When using native size, the size of the packed value is
platform-dependent.
+--------+-------------------------+--------------------+----------------+------------+
| Format | C Type | Python type | Standard size | Notes |
+========+=========================+====================+================+============+
| ``x`` | pad byte | no value | | |
+--------+-------------------------+--------------------+----------------+------------+
| ``c`` | :ctype:`char` | bytes of length 1 | 1 | |
+--------+-------------------------+--------------------+----------------+------------+
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| ``b`` | :ctype:`signed char` | integer | 1 | \(1) |
+--------+-------------------------+--------------------+----------------+------------+
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| ``B`` | :ctype:`unsigned char` | integer | 1 | |
+--------+-------------------------+--------------------+----------------+------------+
| ``?`` | :ctype:`_Bool` | bool | 1 | \(2) |
+--------+-------------------------+--------------------+----------------+------------+
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| ``h`` | :ctype:`short` | integer | 2 | |
+--------+-------------------------+--------------------+----------------+------------+
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| ``H`` | :ctype:`unsigned short` | integer | 2 | |
+--------+-------------------------+--------------------+----------------+------------+
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| ``i`` | :ctype:`int` | integer | 4 | |
+--------+-------------------------+--------------------+----------------+------------+
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| ``I`` | :ctype:`unsigned int` | integer | 4 | |
+--------+-------------------------+--------------------+----------------+------------+
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| ``l`` | :ctype:`long` | integer | 4 | |
+--------+-------------------------+--------------------+----------------+------------+
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| ``L`` | :ctype:`unsigned long` | integer | 4 | |
+--------+-------------------------+--------------------+----------------+------------+
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| ``q`` | :ctype:`long long` | integer | 8 | \(3) |
+--------+-------------------------+--------------------+----------------+------------+
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| ``Q`` | :ctype:`unsigned long | integer | 8 | \(3) |
| | long` | | | |
+--------+-------------------------+--------------------+----------------+------------+
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| ``f`` | :ctype:`float` | float | 4 | \(4) |
+--------+-------------------------+--------------------+----------------+------------+
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| ``d`` | :ctype:`double` | float | 8 | \(4) |
+--------+-------------------------+--------------------+----------------+------------+
| ``s`` | :ctype:`char[]` | bytes | | \(1) |
+--------+-------------------------+--------------------+----------------+------------+
| ``p`` | :ctype:`char[]` | bytes | | \(1) |
+--------+-------------------------+--------------------+----------------+------------+
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| ``P`` | :ctype:`void \*` | integer | | \(5) |
+--------+-------------------------+--------------------+----------------+------------+
Notes:
(1)
The ``c``, ``s`` and ``p`` conversion codes operate on :class:`bytes`
objects, but packing with such codes also supports :class:`str` objects,
which are encoded using UTF-8.
(2)
The ``'?'`` conversion code corresponds to the :ctype:`_Bool` type defined by
C99. If this type is not available, it is simulated using a :ctype:`char`. In
standard mode, it is always represented by one byte.
(3)
The ``'q'`` and ``'Q'`` conversion codes are available in native mode only if
the platform C compiler supports C :ctype:`long long`, or, on Windows,
:ctype:`__int64`. They are always available in standard modes.
(4)
For the ``'f'`` and ``'d'`` conversion codes, the packed representation uses
the IEEE 754 binary32 (for ``'f'``) or binary64 (for ``'d'``) format,
regardless of the floating-point format used by the platform.
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(5)
The ``'P'`` format character is only available for the native byte ordering
(selected as the default or with the ``'@'`` byte order character). The byte
order character ``'='`` chooses to use little- or big-endian ordering based
on the host system. The struct module does not interpret this as native
ordering, so the ``'P'`` format is not available.
A format character may be preceded by an integral repeat count. For example,
the format string ``'4h'`` means exactly the same as ``'hhhh'``.
Whitespace characters between formats are ignored; a count and its format must
not contain whitespace though.
For the ``'s'`` format character, the count is interpreted as the length of the
bytes, not a repeat count like for the other format characters; for example,
``'10s'`` means a single 10-byte string, while ``'10c'`` means 10 characters.
For packing, the string is truncated or padded with null bytes as appropriate to
make it fit. For unpacking, the resulting bytes object always has exactly the
specified number of bytes. As a special case, ``'0s'`` means a single, empty
string (while ``'0c'`` means 0 characters).
When packing a value ``x`` using one of the integer formats (``'b'``,
``'B'``, ``'h'``, ``'H'``, ``'i'``, ``'I'``, ``'l'``, ``'L'``,
``'q'``, ``'Q'``), if ``x`` is outside the valid range for that format
then :exc:`struct.error` is raised.
.. versionchanged:: 3.1
In 3.0, some of the integer formats wrapped out-of-range values and
raised :exc:`DeprecationWarning` instead of :exc:`struct.error`.
The ``'p'`` format character encodes a "Pascal string", meaning a short
variable-length string stored in a fixed number of bytes. The count is the total
number of bytes stored. The first byte stored is the length of the string, or
255, whichever is smaller. The bytes of the string follow. If the string
passed in to :func:`pack` is too long (longer than the count minus 1), only the
leading count-1 bytes of the string are stored. If the string is shorter than
count-1, it is padded with null bytes so that exactly count bytes in all are
used. Note that for :func:`unpack`, the ``'p'`` format character consumes count
bytes, but that the string returned can never contain more than 255 bytes.
For the ``'?'`` format character, the return value is either :const:`True` or
:const:`False`. When packing, the truth value of the argument object is used.
Either 0 or 1 in the native or standard bool representation will be packed, and
any non-zero value will be True when unpacking.
.. _struct-examples:
Examples
^^^^^^^^
.. note::
All examples assume a native byte order, size, and alignment with a
big-endian machine.
A basic example of packing/unpacking three integers::
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>>> from struct import *
>>> pack('hhl', 1, 2, 3)
b'\x00\x01\x00\x02\x00\x00\x00\x03'
>>> unpack('hhl', b'\x00\x01\x00\x02\x00\x00\x00\x03')
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(1, 2, 3)
>>> calcsize('hhl')
8
Merged revisions 63542-63544,63546,63553,63563-63564,63567,63569,63576 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r63542 | mark.dickinson | 2008-05-22 20:35:30 -0500 (Thu, 22 May 2008) | 5 lines Issue #2819: Add math.sum, a function that sums a sequence of floats efficiently but with no intermediate loss of precision. Based on Raymond Hettinger's ASPN recipe. Thanks Jean Brouwers for the patch. ........ r63543 | mark.dickinson | 2008-05-22 21:36:48 -0500 (Thu, 22 May 2008) | 2 lines Add tests for math.sum (Issue #2819) ........ r63544 | mark.dickinson | 2008-05-22 22:30:01 -0500 (Thu, 22 May 2008) | 2 lines Better error reporting in test_math.py ........ r63546 | raymond.hettinger | 2008-05-22 23:32:43 -0500 (Thu, 22 May 2008) | 1 line Tweak the comments and formatting. ........ r63553 | mark.dickinson | 2008-05-23 07:07:36 -0500 (Fri, 23 May 2008) | 3 lines Skip math.sum tests on non IEEE 754 platforms, and on IEEE 754 platforms that exhibit the problem described in issue #2937. ........ r63563 | martin.v.loewis | 2008-05-23 10:18:28 -0500 (Fri, 23 May 2008) | 3 lines Issue #1390: Raise ValueError in toxml when an invalid comment would otherwise be produced. ........ r63564 | raymond.hettinger | 2008-05-23 12:21:44 -0500 (Fri, 23 May 2008) | 1 line Issue 2909: show how to name unpacked fields. ........ r63567 | raymond.hettinger | 2008-05-23 12:34:34 -0500 (Fri, 23 May 2008) | 1 line Fix typo ........ r63569 | martin.v.loewis | 2008-05-23 14:33:13 -0500 (Fri, 23 May 2008) | 3 lines Mention that the leaking of variables from list comprehensions is fixed in 3.0. ........ r63576 | martin.v.loewis | 2008-05-24 04:36:45 -0500 (Sat, 24 May 2008) | 3 lines Don't try to get the window size if it was never set before. Fixes the test failure on Solaris. ........
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Unpacked fields can be named by assigning them to variables or by wrapping
the result in a named tuple::
>>> record = b'raymond \x32\x12\x08\x01\x08'
Merged revisions 63542-63544,63546,63553,63563-63564,63567,63569,63576 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r63542 | mark.dickinson | 2008-05-22 20:35:30 -0500 (Thu, 22 May 2008) | 5 lines Issue #2819: Add math.sum, a function that sums a sequence of floats efficiently but with no intermediate loss of precision. Based on Raymond Hettinger's ASPN recipe. Thanks Jean Brouwers for the patch. ........ r63543 | mark.dickinson | 2008-05-22 21:36:48 -0500 (Thu, 22 May 2008) | 2 lines Add tests for math.sum (Issue #2819) ........ r63544 | mark.dickinson | 2008-05-22 22:30:01 -0500 (Thu, 22 May 2008) | 2 lines Better error reporting in test_math.py ........ r63546 | raymond.hettinger | 2008-05-22 23:32:43 -0500 (Thu, 22 May 2008) | 1 line Tweak the comments and formatting. ........ r63553 | mark.dickinson | 2008-05-23 07:07:36 -0500 (Fri, 23 May 2008) | 3 lines Skip math.sum tests on non IEEE 754 platforms, and on IEEE 754 platforms that exhibit the problem described in issue #2937. ........ r63563 | martin.v.loewis | 2008-05-23 10:18:28 -0500 (Fri, 23 May 2008) | 3 lines Issue #1390: Raise ValueError in toxml when an invalid comment would otherwise be produced. ........ r63564 | raymond.hettinger | 2008-05-23 12:21:44 -0500 (Fri, 23 May 2008) | 1 line Issue 2909: show how to name unpacked fields. ........ r63567 | raymond.hettinger | 2008-05-23 12:34:34 -0500 (Fri, 23 May 2008) | 1 line Fix typo ........ r63569 | martin.v.loewis | 2008-05-23 14:33:13 -0500 (Fri, 23 May 2008) | 3 lines Mention that the leaking of variables from list comprehensions is fixed in 3.0. ........ r63576 | martin.v.loewis | 2008-05-24 04:36:45 -0500 (Sat, 24 May 2008) | 3 lines Don't try to get the window size if it was never set before. Fixes the test failure on Solaris. ........
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>>> name, serialnum, school, gradelevel = unpack('<10sHHb', record)
>>> from collections import namedtuple
>>> Student = namedtuple('Student', 'name serialnum school gradelevel')
>>> Student._make(unpack('<10sHHb', record))
Student(name=b'raymond ', serialnum=4658, school=264, gradelevel=8)
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The ordering of format characters may have an impact on size since the padding
needed to satisfy alignment requirements is different::
>>> pack('ci', '*', 0x12131415)
b'*\x00\x00\x00\x12\x13\x14\x15'
>>> pack('ic', 0x12131415, '*')
b'\x12\x13\x14\x15*'
>>> calcsize('ci')
8
>>> calcsize('ic')
5
The following format ``'llh0l'`` specifies two pad bytes at the end, assuming
longs are aligned on 4-byte boundaries::
>>> pack('llh0l', 1, 2, 3)
b'\x00\x00\x00\x01\x00\x00\x00\x02\x00\x03\x00\x00'
This only works when native size and alignment are in effect; standard size and
alignment does not enforce any alignment.
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.. seealso::
Module :mod:`array`
Packed binary storage of homogeneous data.
Module :mod:`xdrlib`
Packing and unpacking of XDR data.
.. _struct-objects:
Classes
-------
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The :mod:`struct` module also defines the following type:
.. class:: Struct(format)
Return a new Struct object which writes and reads binary data according to
the format string *format*. Creating a Struct object once and calling its
methods is more efficient than calling the :mod:`struct` functions with the
same format since the format string only needs to be compiled once.
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Compiled Struct objects support the following methods and attributes:
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.. method:: pack(v1, v2, ...)
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Identical to the :func:`pack` function, using the compiled format.
(``len(result)`` will equal :attr:`self.size`.)
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.. method:: pack_into(buffer, offset, v1, v2, ...)
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Identical to the :func:`pack_into` function, using the compiled format.
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.. method:: unpack(buffer)
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Identical to the :func:`unpack` function, using the compiled format.
(``len(buffer)`` must equal :attr:`self.size`).
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Merged revisions 74821,74828-74831,74833,74835 via svnmerge from svn+ssh://svn.python.org/python/branches/py3k ................ r74821 | georg.brandl | 2009-09-16 11:42:19 +0200 (Mi, 16 Sep 2009) | 1 line #6885: run python 3 as python3. ................ r74828 | georg.brandl | 2009-09-16 16:23:20 +0200 (Mi, 16 Sep 2009) | 1 line Use true booleans. ................ r74829 | georg.brandl | 2009-09-16 16:24:29 +0200 (Mi, 16 Sep 2009) | 1 line Small PEP8 correction. ................ r74830 | georg.brandl | 2009-09-16 16:36:22 +0200 (Mi, 16 Sep 2009) | 1 line Use true booleans. ................ r74831 | georg.brandl | 2009-09-16 17:54:04 +0200 (Mi, 16 Sep 2009) | 1 line Use true booleans and PEP8 for argdefaults. ................ r74833 | georg.brandl | 2009-09-16 17:58:14 +0200 (Mi, 16 Sep 2009) | 1 line Last round of adapting style of documenting argument default values. ................ r74835 | georg.brandl | 2009-09-16 18:00:31 +0200 (Mi, 16 Sep 2009) | 33 lines Merged revisions 74817-74820,74822-74824 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r74817 | georg.brandl | 2009-09-16 11:05:11 +0200 (Mi, 16 Sep 2009) | 1 line Make deprecation notices as visible as warnings are right now. ........ r74818 | georg.brandl | 2009-09-16 11:23:04 +0200 (Mi, 16 Sep 2009) | 1 line #6880: add reference to classes section in exceptions section, which comes earlier. ........ r74819 | georg.brandl | 2009-09-16 11:24:57 +0200 (Mi, 16 Sep 2009) | 1 line #6876: fix base class constructor invocation in example. ........ r74820 | georg.brandl | 2009-09-16 11:30:48 +0200 (Mi, 16 Sep 2009) | 1 line #6891: comment out dead link to Unicode article. ........ r74822 | georg.brandl | 2009-09-16 12:12:06 +0200 (Mi, 16 Sep 2009) | 1 line #5621: refactor description of how class/instance attributes interact on a.x=a.x+1 or augassign. ........ r74823 | georg.brandl | 2009-09-16 15:06:22 +0200 (Mi, 16 Sep 2009) | 1 line Remove strange trailing commas. ........ r74824 | georg.brandl | 2009-09-16 15:11:06 +0200 (Mi, 16 Sep 2009) | 1 line #6892: fix optparse example involving help option. ........ ................
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.. method:: unpack_from(buffer, offset=0)
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Identical to the :func:`unpack_from` function, using the compiled format.
(``len(buffer[offset:])`` must be at least :attr:`self.size`).
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.. attribute:: format
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The format string used to construct this Struct object.
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.. attribute:: size
Merged revisions 57221-57391 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r57227 | facundo.batista | 2007-08-20 17:16:21 -0700 (Mon, 20 Aug 2007) | 5 lines Catch ProtocolError exceptions and include the header information in test output (to make it easier to debug test failures caused by problems in the server). [GSoC - Alan McIntyre] ........ r57229 | mark.hammond | 2007-08-20 18:04:47 -0700 (Mon, 20 Aug 2007) | 5 lines [ 1761786 ] distutils.util.get_platform() return value on 64bit Windows As discussed on distutils-sig: Allows the generated installer name on 64bit Windows platforms to be different than the name generated for 32bit Windows platforms. ........ r57230 | mark.hammond | 2007-08-20 18:05:16 -0700 (Mon, 20 Aug 2007) | 5 lines [ 1761786 ] distutils.util.get_platform() return value on 64bit Windows As discussed on distutils-sig: Allows the generated installer name on 64bit Windows platforms to be different than the name generated for 32bit Windows platforms. ........ r57253 | georg.brandl | 2007-08-20 23:01:18 -0700 (Mon, 20 Aug 2007) | 2 lines Demand version 2.5.1 since 2.5 has a bug with codecs.open context managers. ........ r57254 | georg.brandl | 2007-08-20 23:03:43 -0700 (Mon, 20 Aug 2007) | 2 lines Revert accidental checkins from last commit. ........ r57255 | georg.brandl | 2007-08-20 23:07:08 -0700 (Mon, 20 Aug 2007) | 2 lines Bug #1777160: mention explicitly that e.g. -1**2 is -1. ........ r57256 | georg.brandl | 2007-08-20 23:12:19 -0700 (Mon, 20 Aug 2007) | 3 lines Bug #1777168: replace operator names "opa"... with "op1"... and mark everything up as literal, to enhance readability. ........ r57259 | facundo.batista | 2007-08-21 09:57:18 -0700 (Tue, 21 Aug 2007) | 8 lines Added test for behavior of operations on an unconnected SMTP object, and tests for NOOP, RSET, and VRFY. Corrected typo in a comment for testNonnumericPort. Added a check for constructing SMTP objects when non-numeric ports are included in the host name. Derived a server from SMTPServer to test various ESMTP/SMTP capabilities. Check that a second HELO to DebuggingServer returns an error. [GSoC - Alan McIntyre] ........ r57279 | skip.montanaro | 2007-08-22 12:02:16 -0700 (Wed, 22 Aug 2007) | 2 lines Note that BeOS is unsupported as of Python 2.6. ........ r57280 | skip.montanaro | 2007-08-22 12:05:21 -0700 (Wed, 22 Aug 2007) | 1 line whoops - need to check in configure as well ........ r57284 | alex.martelli | 2007-08-22 14:14:17 -0700 (Wed, 22 Aug 2007) | 5 lines Fix compile.c so that it records 0.0 and -0.0 as separate constants in a code object's co_consts tuple; add a test to show that the previous behavior (where these two constants were "collapsed" into one) causes serious malfunctioning. ........ r57286 | gregory.p.smith | 2007-08-22 14:32:34 -0700 (Wed, 22 Aug 2007) | 3 lines stop leaving log.0000001 __db.00* and xxx.db turds in developer sandboxes when bsddb3 tests are run. ........ r57301 | jeffrey.yasskin | 2007-08-22 16:14:27 -0700 (Wed, 22 Aug 2007) | 3 lines When setup.py fails to find the necessary bits to build some modules, have it print a slightly more informative message. ........ r57320 | brett.cannon | 2007-08-23 07:53:17 -0700 (Thu, 23 Aug 2007) | 2 lines Make test_runpy re-entrant. ........ r57324 | georg.brandl | 2007-08-23 10:54:11 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1768121: fix wrong/missing opcode docs. ........ r57326 | georg.brandl | 2007-08-23 10:57:05 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1766421: "return code" vs. "status code". ........ r57328 | georg.brandl | 2007-08-23 11:08:06 -0700 (Thu, 23 Aug 2007) | 2 lines Second half of #1752175: #ifdef out references to PyImport_DynLoadFiletab if HAVE_DYNAMIC_LOADING is not defined. ........ r57331 | georg.brandl | 2007-08-23 11:11:33 -0700 (Thu, 23 Aug 2007) | 2 lines Use try-except-finally in contextlib. ........ r57343 | georg.brandl | 2007-08-23 13:35:00 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1697820: document that the old slice protocol is still used by builtin types. ........ r57345 | georg.brandl | 2007-08-23 13:40:01 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1573854: fix docs for sqlite3 cursor rowcount attr. ........ r57347 | georg.brandl | 2007-08-23 13:50:23 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1694833: fix imp.find_module() docs wrt. packages. ........ r57348 | georg.brandl | 2007-08-23 13:53:28 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1594966: fix misleading usage example ........ r57349 | georg.brandl | 2007-08-23 13:55:44 -0700 (Thu, 23 Aug 2007) | 2 lines Clarify wording a bit. ........ r57351 | georg.brandl | 2007-08-23 14:18:44 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1752332: httplib no longer uses socket.getaddrinfo(). ........ r57352 | georg.brandl | 2007-08-23 14:21:36 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1734111: document struct.Struct.size. ........ r57353 | georg.brandl | 2007-08-23 14:27:57 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1688564: document os.path.join's absolute path behavior in the docstring. ........ r57354 | georg.brandl | 2007-08-23 14:36:05 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1625381: clarify match vs search introduction. ........ r57355 | georg.brandl | 2007-08-23 14:42:54 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1758696: more info about descriptors. ........ r57357 | georg.brandl | 2007-08-23 14:55:57 -0700 (Thu, 23 Aug 2007) | 2 lines Patch #1779550: remove redundant code in logging. ........ r57378 | gregory.p.smith | 2007-08-23 22:11:38 -0700 (Thu, 23 Aug 2007) | 2 lines Fix bug 1725856. ........ r57382 | georg.brandl | 2007-08-23 23:10:01 -0700 (Thu, 23 Aug 2007) | 2 lines uuid creation is now threadsafe, backport from py3k rev. 57375. ........ r57389 | georg.brandl | 2007-08-24 04:47:37 -0700 (Fri, 24 Aug 2007) | 2 lines Bug #1765375: fix stripping of unwanted LDFLAGS. ........ r57391 | guido.van.rossum | 2007-08-24 07:53:14 -0700 (Fri, 24 Aug 2007) | 2 lines Fix silly typo in test name. ........
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The calculated size of the struct (and hence of the bytes object produced
by the :meth:`pack` method) corresponding to :attr:`format`.
Merged revisions 57221-57391 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r57227 | facundo.batista | 2007-08-20 17:16:21 -0700 (Mon, 20 Aug 2007) | 5 lines Catch ProtocolError exceptions and include the header information in test output (to make it easier to debug test failures caused by problems in the server). [GSoC - Alan McIntyre] ........ r57229 | mark.hammond | 2007-08-20 18:04:47 -0700 (Mon, 20 Aug 2007) | 5 lines [ 1761786 ] distutils.util.get_platform() return value on 64bit Windows As discussed on distutils-sig: Allows the generated installer name on 64bit Windows platforms to be different than the name generated for 32bit Windows platforms. ........ r57230 | mark.hammond | 2007-08-20 18:05:16 -0700 (Mon, 20 Aug 2007) | 5 lines [ 1761786 ] distutils.util.get_platform() return value on 64bit Windows As discussed on distutils-sig: Allows the generated installer name on 64bit Windows platforms to be different than the name generated for 32bit Windows platforms. ........ r57253 | georg.brandl | 2007-08-20 23:01:18 -0700 (Mon, 20 Aug 2007) | 2 lines Demand version 2.5.1 since 2.5 has a bug with codecs.open context managers. ........ r57254 | georg.brandl | 2007-08-20 23:03:43 -0700 (Mon, 20 Aug 2007) | 2 lines Revert accidental checkins from last commit. ........ r57255 | georg.brandl | 2007-08-20 23:07:08 -0700 (Mon, 20 Aug 2007) | 2 lines Bug #1777160: mention explicitly that e.g. -1**2 is -1. ........ r57256 | georg.brandl | 2007-08-20 23:12:19 -0700 (Mon, 20 Aug 2007) | 3 lines Bug #1777168: replace operator names "opa"... with "op1"... and mark everything up as literal, to enhance readability. ........ r57259 | facundo.batista | 2007-08-21 09:57:18 -0700 (Tue, 21 Aug 2007) | 8 lines Added test for behavior of operations on an unconnected SMTP object, and tests for NOOP, RSET, and VRFY. Corrected typo in a comment for testNonnumericPort. Added a check for constructing SMTP objects when non-numeric ports are included in the host name. Derived a server from SMTPServer to test various ESMTP/SMTP capabilities. Check that a second HELO to DebuggingServer returns an error. [GSoC - Alan McIntyre] ........ r57279 | skip.montanaro | 2007-08-22 12:02:16 -0700 (Wed, 22 Aug 2007) | 2 lines Note that BeOS is unsupported as of Python 2.6. ........ r57280 | skip.montanaro | 2007-08-22 12:05:21 -0700 (Wed, 22 Aug 2007) | 1 line whoops - need to check in configure as well ........ r57284 | alex.martelli | 2007-08-22 14:14:17 -0700 (Wed, 22 Aug 2007) | 5 lines Fix compile.c so that it records 0.0 and -0.0 as separate constants in a code object's co_consts tuple; add a test to show that the previous behavior (where these two constants were "collapsed" into one) causes serious malfunctioning. ........ r57286 | gregory.p.smith | 2007-08-22 14:32:34 -0700 (Wed, 22 Aug 2007) | 3 lines stop leaving log.0000001 __db.00* and xxx.db turds in developer sandboxes when bsddb3 tests are run. ........ r57301 | jeffrey.yasskin | 2007-08-22 16:14:27 -0700 (Wed, 22 Aug 2007) | 3 lines When setup.py fails to find the necessary bits to build some modules, have it print a slightly more informative message. ........ r57320 | brett.cannon | 2007-08-23 07:53:17 -0700 (Thu, 23 Aug 2007) | 2 lines Make test_runpy re-entrant. ........ r57324 | georg.brandl | 2007-08-23 10:54:11 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1768121: fix wrong/missing opcode docs. ........ r57326 | georg.brandl | 2007-08-23 10:57:05 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1766421: "return code" vs. "status code". ........ r57328 | georg.brandl | 2007-08-23 11:08:06 -0700 (Thu, 23 Aug 2007) | 2 lines Second half of #1752175: #ifdef out references to PyImport_DynLoadFiletab if HAVE_DYNAMIC_LOADING is not defined. ........ r57331 | georg.brandl | 2007-08-23 11:11:33 -0700 (Thu, 23 Aug 2007) | 2 lines Use try-except-finally in contextlib. ........ r57343 | georg.brandl | 2007-08-23 13:35:00 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1697820: document that the old slice protocol is still used by builtin types. ........ r57345 | georg.brandl | 2007-08-23 13:40:01 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1573854: fix docs for sqlite3 cursor rowcount attr. ........ r57347 | georg.brandl | 2007-08-23 13:50:23 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1694833: fix imp.find_module() docs wrt. packages. ........ r57348 | georg.brandl | 2007-08-23 13:53:28 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1594966: fix misleading usage example ........ r57349 | georg.brandl | 2007-08-23 13:55:44 -0700 (Thu, 23 Aug 2007) | 2 lines Clarify wording a bit. ........ r57351 | georg.brandl | 2007-08-23 14:18:44 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1752332: httplib no longer uses socket.getaddrinfo(). ........ r57352 | georg.brandl | 2007-08-23 14:21:36 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1734111: document struct.Struct.size. ........ r57353 | georg.brandl | 2007-08-23 14:27:57 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1688564: document os.path.join's absolute path behavior in the docstring. ........ r57354 | georg.brandl | 2007-08-23 14:36:05 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1625381: clarify match vs search introduction. ........ r57355 | georg.brandl | 2007-08-23 14:42:54 -0700 (Thu, 23 Aug 2007) | 2 lines Bug #1758696: more info about descriptors. ........ r57357 | georg.brandl | 2007-08-23 14:55:57 -0700 (Thu, 23 Aug 2007) | 2 lines Patch #1779550: remove redundant code in logging. ........ r57378 | gregory.p.smith | 2007-08-23 22:11:38 -0700 (Thu, 23 Aug 2007) | 2 lines Fix bug 1725856. ........ r57382 | georg.brandl | 2007-08-23 23:10:01 -0700 (Thu, 23 Aug 2007) | 2 lines uuid creation is now threadsafe, backport from py3k rev. 57375. ........ r57389 | georg.brandl | 2007-08-24 04:47:37 -0700 (Fri, 24 Aug 2007) | 2 lines Bug #1765375: fix stripping of unwanted LDFLAGS. ........ r57391 | guido.van.rossum | 2007-08-24 07:53:14 -0700 (Fri, 24 Aug 2007) | 2 lines Fix silly typo in test name. ........
2007-08-24 13:32:05 -03:00