2007-08-15 22:28:22 +08:00
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:mod:`binascii` --- Convert between binary and ASCII
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====================================================
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.. module:: binascii
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:synopsis: Tools for converting between binary and various ASCII-encoded binary
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representations.
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.. index::
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module: uu
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module: base64
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module: binhex
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The :mod:`binascii` module contains a number of methods to convert between
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binary and various ASCII-encoded binary representations. Normally, you will not
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use these functions directly but use wrapper modules like :mod:`uu`,
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:mod:`base64`, or :mod:`binhex` instead. The :mod:`binascii` module contains
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low-level functions written in C for greater speed that are used by the
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higher-level modules.
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2010-07-28 05:20:15 +08:00
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.. note::
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Encoding and decoding functions do not accept Unicode strings. Only bytestring
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and bytearray objects can be processed.
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2007-08-15 22:28:22 +08:00
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The :mod:`binascii` module defines the following functions:
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.. function:: a2b_uu(string)
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Convert a single line of uuencoded data back to binary and return the binary
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data. Lines normally contain 45 (binary) bytes, except for the last line. Line
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data may be followed by whitespace.
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.. function:: b2a_uu(data)
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Convert binary data to a line of ASCII characters, the return value is the
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converted line, including a newline char. The length of *data* should be at most
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45.
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.. function:: a2b_base64(string)
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Convert a block of base64 data back to binary and return the binary data. More
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than one line may be passed at a time.
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.. function:: b2a_base64(data)
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Convert binary data to a line of ASCII characters in base64 coding. The return
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value is the converted line, including a newline char. The length of *data*
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should be at most 57 to adhere to the base64 standard.
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2009-04-02 10:56:10 +08:00
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.. function:: a2b_qp(string, header=False)
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2007-08-15 22:28:22 +08:00
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Convert a block of quoted-printable data back to binary and return the binary
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data. More than one line may be passed at a time. If the optional argument
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*header* is present and true, underscores will be decoded as spaces.
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2010-07-28 05:20:15 +08:00
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.. versionchanged:: 3.2
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2010-08-17 23:07:14 +08:00
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Accept only bytestring or bytearray objects as input.
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2010-07-28 05:20:15 +08:00
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2007-08-15 22:28:22 +08:00
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2009-04-02 10:56:10 +08:00
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.. function:: b2a_qp(data, quotetabs=False, istext=True, header=False)
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2007-08-15 22:28:22 +08:00
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Convert binary data to a line(s) of ASCII characters in quoted-printable
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encoding. The return value is the converted line(s). If the optional argument
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*quotetabs* is present and true, all tabs and spaces will be encoded. If the
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optional argument *istext* is present and true, newlines are not encoded but
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trailing whitespace will be encoded. If the optional argument *header* is
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present and true, spaces will be encoded as underscores per RFC1522. If the
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optional argument *header* is present and false, newline characters will be
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encoded as well; otherwise linefeed conversion might corrupt the binary data
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stream.
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.. function:: a2b_hqx(string)
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Convert binhex4 formatted ASCII data to binary, without doing RLE-decompression.
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The string should contain a complete number of binary bytes, or (in case of the
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last portion of the binhex4 data) have the remaining bits zero.
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.. function:: rledecode_hqx(data)
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Perform RLE-decompression on the data, as per the binhex4 standard. The
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algorithm uses ``0x90`` after a byte as a repeat indicator, followed by a count.
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A count of ``0`` specifies a byte value of ``0x90``. The routine returns the
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decompressed data, unless data input data ends in an orphaned repeat indicator,
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in which case the :exc:`Incomplete` exception is raised.
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2010-07-28 05:20:15 +08:00
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.. versionchanged:: 3.2
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2010-08-17 23:07:14 +08:00
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Accept only bytestring or bytearray objects as input.
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2010-07-28 05:20:15 +08:00
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2007-08-15 22:28:22 +08:00
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.. function:: rlecode_hqx(data)
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Perform binhex4 style RLE-compression on *data* and return the result.
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.. function:: b2a_hqx(data)
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Perform hexbin4 binary-to-ASCII translation and return the resulting string. The
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argument should already be RLE-coded, and have a length divisible by 3 (except
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possibly the last fragment).
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.. function:: crc_hqx(data, crc)
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Compute the binhex4 crc value of *data*, starting with an initial *crc* and
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returning the result.
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.. function:: crc32(data[, crc])
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Compute CRC-32, the 32-bit checksum of data, starting with an initial crc. This
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is consistent with the ZIP file checksum. Since the algorithm is designed for
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use as a checksum algorithm, it is not suitable for use as a general hash
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algorithm. Use as follows::
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2010-01-05 18:22:04 +08:00
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print(binascii.crc32(b"hello world"))
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2007-08-15 22:28:22 +08:00
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# Or, in two pieces:
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2010-01-05 18:22:04 +08:00
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crc = binascii.crc32(b"hello")
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crc = binascii.crc32(b" world", crc) & 0xffffffff
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print('crc32 = {:#010x}'.format(crc))
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Merged revisions 68450,68480-68481,68493,68495,68501,68512,68514-68515,68534-68536,68552,68563,68570-68572,68575,68582,68596,68623-68624,68628 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r68450 | jeffrey.yasskin | 2009-01-09 10:47:07 -0600 (Fri, 09 Jan 2009) | 3 lines
Fix issue 4884, preventing a crash in the socket code when python is compiled
with llvm-gcc and run with a glibc <2.10.
........
r68480 | vinay.sajip | 2009-01-10 07:38:04 -0600 (Sat, 10 Jan 2009) | 1 line
Minor documentation changes cross-referencing NullHandler to the documentation on configuring logging in a library.
........
r68481 | vinay.sajip | 2009-01-10 07:42:04 -0600 (Sat, 10 Jan 2009) | 1 line
Corrected an incorrect self-reference.
........
r68493 | benjamin.peterson | 2009-01-10 11:18:55 -0600 (Sat, 10 Jan 2009) | 1 line
rewrite verbose conditionals
........
r68495 | benjamin.peterson | 2009-01-10 11:36:44 -0600 (Sat, 10 Jan 2009) | 1 line
tp_iter only exists with Py_TPFLAGS_HAVE_ITER #4901
........
r68501 | vinay.sajip | 2009-01-10 13:22:57 -0600 (Sat, 10 Jan 2009) | 1 line
Corrected minor typo and added .currentmodule directives to fix missing cross-references.
........
r68512 | benjamin.peterson | 2009-01-10 16:42:10 -0600 (Sat, 10 Jan 2009) | 1 line
make tests fail if they can't be imported
........
r68514 | benjamin.peterson | 2009-01-10 17:41:59 -0600 (Sat, 10 Jan 2009) | 1 line
move seealso to a more appropiate place
........
r68515 | benjamin.peterson | 2009-01-10 17:49:08 -0600 (Sat, 10 Jan 2009) | 1 line
macos 9 isn't supported
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r68534 | gregory.p.smith | 2009-01-11 11:53:33 -0600 (Sun, 11 Jan 2009) | 2 lines
correct email address
........
r68535 | gregory.p.smith | 2009-01-11 11:57:54 -0600 (Sun, 11 Jan 2009) | 9 lines
Update the documentation for binascii and zlib crc32/adler32 functions
to better describe the signed vs unsigned return value behavior on
different platforms and versions of python. Mention the workaround to
make them all return the same thing by using & 0xffffffff.
Fixes issue4903.
Also needs to be merged into release26-maint, release30-maint, & py3k.
........
r68536 | benjamin.peterson | 2009-01-11 13:48:15 -0600 (Sun, 11 Jan 2009) | 1 line
add email addresses
........
r68552 | vinay.sajip | 2009-01-12 14:36:18 -0600 (Mon, 12 Jan 2009) | 1 line
Minor changes/corrections in markup.
........
r68563 | benjamin.peterson | 2009-01-12 19:49:10 -0600 (Mon, 12 Jan 2009) | 1 line
small logic correction
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r68570 | raymond.hettinger | 2009-01-13 03:08:32 -0600 (Tue, 13 Jan 2009) | 5 lines
Issue 4922: Incorrect comments for MutableSet.add() and MutableSet.discard().
Needs to be backported to 2.6 and forward ported to 3.0 and 3.1.
........
r68571 | armin.ronacher | 2009-01-13 05:52:23 -0600 (Tue, 13 Jan 2009) | 3 lines
ast.literal_eval can properly evaluate complex numbers now. This fixes issue4907.
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r68572 | andrew.kuchling | 2009-01-13 07:40:54 -0600 (Tue, 13 Jan 2009) | 1 line
Note that first coord. is left alone
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r68575 | thomas.heller | 2009-01-13 11:32:28 -0600 (Tue, 13 Jan 2009) | 1 line
Fix refcount leak in error cases. Bug found by coverity.
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r68582 | georg.brandl | 2009-01-13 16:14:01 -0600 (Tue, 13 Jan 2009) | 2 lines
Use assertRaises.
........
r68596 | amaury.forgeotdarc | 2009-01-13 17:39:22 -0600 (Tue, 13 Jan 2009) | 3 lines
#1162154: inspect.getmembers() now skips attributes that raise AttributeError,
e.g. a __slots__ attribute which has not been set.
........
r68623 | vinay.sajip | 2009-01-15 16:48:13 -0600 (Thu, 15 Jan 2009) | 1 line
Made minor changes/corrections in markup. Added a couple of section headings.
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r68624 | vinay.sajip | 2009-01-15 17:04:47 -0600 (Thu, 15 Jan 2009) | 1 line
Minor changes/corrections in markup.
........
r68628 | benjamin.peterson | 2009-01-15 20:55:24 -0600 (Thu, 15 Jan 2009) | 1 line
compare with == not is #4946
........
2009-01-16 11:54:08 +08:00
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.. note::
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To generate the same numeric value across all Python versions and
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platforms use crc32(data) & 0xffffffff. If you are only using
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the checksum in packed binary format this is not necessary as the
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2009-02-01 08:30:50 +08:00
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return value is the correct 32bit binary representation
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Merged revisions 68450,68480-68481,68493,68495,68501,68512,68514-68515,68534-68536,68552,68563,68570-68572,68575,68582,68596,68623-68624,68628 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r68450 | jeffrey.yasskin | 2009-01-09 10:47:07 -0600 (Fri, 09 Jan 2009) | 3 lines
Fix issue 4884, preventing a crash in the socket code when python is compiled
with llvm-gcc and run with a glibc <2.10.
........
r68480 | vinay.sajip | 2009-01-10 07:38:04 -0600 (Sat, 10 Jan 2009) | 1 line
Minor documentation changes cross-referencing NullHandler to the documentation on configuring logging in a library.
........
r68481 | vinay.sajip | 2009-01-10 07:42:04 -0600 (Sat, 10 Jan 2009) | 1 line
Corrected an incorrect self-reference.
........
r68493 | benjamin.peterson | 2009-01-10 11:18:55 -0600 (Sat, 10 Jan 2009) | 1 line
rewrite verbose conditionals
........
r68495 | benjamin.peterson | 2009-01-10 11:36:44 -0600 (Sat, 10 Jan 2009) | 1 line
tp_iter only exists with Py_TPFLAGS_HAVE_ITER #4901
........
r68501 | vinay.sajip | 2009-01-10 13:22:57 -0600 (Sat, 10 Jan 2009) | 1 line
Corrected minor typo and added .currentmodule directives to fix missing cross-references.
........
r68512 | benjamin.peterson | 2009-01-10 16:42:10 -0600 (Sat, 10 Jan 2009) | 1 line
make tests fail if they can't be imported
........
r68514 | benjamin.peterson | 2009-01-10 17:41:59 -0600 (Sat, 10 Jan 2009) | 1 line
move seealso to a more appropiate place
........
r68515 | benjamin.peterson | 2009-01-10 17:49:08 -0600 (Sat, 10 Jan 2009) | 1 line
macos 9 isn't supported
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r68534 | gregory.p.smith | 2009-01-11 11:53:33 -0600 (Sun, 11 Jan 2009) | 2 lines
correct email address
........
r68535 | gregory.p.smith | 2009-01-11 11:57:54 -0600 (Sun, 11 Jan 2009) | 9 lines
Update the documentation for binascii and zlib crc32/adler32 functions
to better describe the signed vs unsigned return value behavior on
different platforms and versions of python. Mention the workaround to
make them all return the same thing by using & 0xffffffff.
Fixes issue4903.
Also needs to be merged into release26-maint, release30-maint, & py3k.
........
r68536 | benjamin.peterson | 2009-01-11 13:48:15 -0600 (Sun, 11 Jan 2009) | 1 line
add email addresses
........
r68552 | vinay.sajip | 2009-01-12 14:36:18 -0600 (Mon, 12 Jan 2009) | 1 line
Minor changes/corrections in markup.
........
r68563 | benjamin.peterson | 2009-01-12 19:49:10 -0600 (Mon, 12 Jan 2009) | 1 line
small logic correction
........
r68570 | raymond.hettinger | 2009-01-13 03:08:32 -0600 (Tue, 13 Jan 2009) | 5 lines
Issue 4922: Incorrect comments for MutableSet.add() and MutableSet.discard().
Needs to be backported to 2.6 and forward ported to 3.0 and 3.1.
........
r68571 | armin.ronacher | 2009-01-13 05:52:23 -0600 (Tue, 13 Jan 2009) | 3 lines
ast.literal_eval can properly evaluate complex numbers now. This fixes issue4907.
........
r68572 | andrew.kuchling | 2009-01-13 07:40:54 -0600 (Tue, 13 Jan 2009) | 1 line
Note that first coord. is left alone
........
r68575 | thomas.heller | 2009-01-13 11:32:28 -0600 (Tue, 13 Jan 2009) | 1 line
Fix refcount leak in error cases. Bug found by coverity.
........
r68582 | georg.brandl | 2009-01-13 16:14:01 -0600 (Tue, 13 Jan 2009) | 2 lines
Use assertRaises.
........
r68596 | amaury.forgeotdarc | 2009-01-13 17:39:22 -0600 (Tue, 13 Jan 2009) | 3 lines
#1162154: inspect.getmembers() now skips attributes that raise AttributeError,
e.g. a __slots__ attribute which has not been set.
........
r68623 | vinay.sajip | 2009-01-15 16:48:13 -0600 (Thu, 15 Jan 2009) | 1 line
Made minor changes/corrections in markup. Added a couple of section headings.
........
r68624 | vinay.sajip | 2009-01-15 17:04:47 -0600 (Thu, 15 Jan 2009) | 1 line
Minor changes/corrections in markup.
........
r68628 | benjamin.peterson | 2009-01-15 20:55:24 -0600 (Thu, 15 Jan 2009) | 1 line
compare with == not is #4946
........
2009-01-16 11:54:08 +08:00
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regardless of sign.
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2007-08-15 22:28:22 +08:00
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.. function:: b2a_hex(data)
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hexlify(data)
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Return the hexadecimal representation of the binary *data*. Every byte of
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*data* is converted into the corresponding 2-digit hex representation. The
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resulting string is therefore twice as long as the length of *data*.
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.. function:: a2b_hex(hexstr)
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unhexlify(hexstr)
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Return the binary data represented by the hexadecimal string *hexstr*. This
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function is the inverse of :func:`b2a_hex`. *hexstr* must contain an even number
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of hexadecimal digits (which can be upper or lower case), otherwise a
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:exc:`TypeError` is raised.
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2010-07-28 05:20:15 +08:00
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.. versionchanged:: 3.2
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2010-08-17 23:07:14 +08:00
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Accept only bytestring or bytearray objects as input.
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2010-07-28 05:20:15 +08:00
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2007-08-15 22:28:22 +08:00
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.. exception:: Error
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Exception raised on errors. These are usually programming errors.
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.. exception:: Incomplete
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Exception raised on incomplete data. These are usually not programming errors,
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but may be handled by reading a little more data and trying again.
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.. seealso::
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Module :mod:`base64`
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Support for base64 encoding used in MIME email messages.
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Module :mod:`binhex`
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Support for the binhex format used on the Macintosh.
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Module :mod:`uu`
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Support for UU encoding used on Unix.
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Module :mod:`quopri`
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Support for quoted-printable encoding used in MIME email messages.
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