mirror of
https://github.com/python/cpython.git
synced 2025-11-03 19:34:08 +00:00
171 lines
5.6 KiB
ReStructuredText
171 lines
5.6 KiB
ReStructuredText
:mod:`unicodedata` --- Unicode Database
|
|
=======================================
|
|
|
|
.. module:: unicodedata
|
|
:synopsis: Access the Unicode Database.
|
|
.. moduleauthor:: Marc-André Lemburg <mal@lemburg.com>
|
|
.. sectionauthor:: Marc-André Lemburg <mal@lemburg.com>
|
|
.. sectionauthor:: Martin v. Löwis <martin@v.loewis.de>
|
|
|
|
|
|
.. index::
|
|
single: Unicode
|
|
single: character
|
|
pair: Unicode; database
|
|
|
|
This module provides access to the Unicode Character Database (UCD) which
|
|
defines character properties for all Unicode characters. The data contained in
|
|
this database is compiled from the `UCD version 8.0.0
|
|
<http://www.unicode.org/Public/8.0.0/ucd>`_.
|
|
|
|
The module uses the same names and symbols as defined by Unicode
|
|
Standard Annex #44, `"Unicode Character Database"
|
|
<http://www.unicode.org/reports/tr44/tr44-6.html>`_. It defines the
|
|
following functions:
|
|
|
|
|
|
.. function:: lookup(name)
|
|
|
|
Look up character by name. If a character with the given name is found, return
|
|
the corresponding character. If not found, :exc:`KeyError` is raised.
|
|
|
|
.. versionchanged:: 3.3
|
|
Support for name aliases [#]_ and named sequences [#]_ has been added.
|
|
|
|
|
|
.. function:: name(chr[, default])
|
|
|
|
Returns the name assigned to the character *chr* as a string. If no
|
|
name is defined, *default* is returned, or, if not given, :exc:`ValueError` is
|
|
raised.
|
|
|
|
|
|
.. function:: decimal(chr[, default])
|
|
|
|
Returns the decimal value assigned to the character *chr* as integer.
|
|
If no such value is defined, *default* is returned, or, if not given,
|
|
:exc:`ValueError` is raised.
|
|
|
|
|
|
.. function:: digit(chr[, default])
|
|
|
|
Returns the digit value assigned to the character *chr* as integer.
|
|
If no such value is defined, *default* is returned, or, if not given,
|
|
:exc:`ValueError` is raised.
|
|
|
|
|
|
.. function:: numeric(chr[, default])
|
|
|
|
Returns the numeric value assigned to the character *chr* as float.
|
|
If no such value is defined, *default* is returned, or, if not given,
|
|
:exc:`ValueError` is raised.
|
|
|
|
|
|
.. function:: category(chr)
|
|
|
|
Returns the general category assigned to the character *chr* as
|
|
string.
|
|
|
|
|
|
.. function:: bidirectional(chr)
|
|
|
|
Returns the bidirectional class assigned to the character *chr* as
|
|
string. If no such value is defined, an empty string is returned.
|
|
|
|
|
|
.. function:: combining(chr)
|
|
|
|
Returns the canonical combining class assigned to the character *chr*
|
|
as integer. Returns ``0`` if no combining class is defined.
|
|
|
|
|
|
.. function:: east_asian_width(chr)
|
|
|
|
Returns the east asian width assigned to the character *chr* as
|
|
string.
|
|
|
|
|
|
.. function:: mirrored(chr)
|
|
|
|
Returns the mirrored property assigned to the character *chr* as
|
|
integer. Returns ``1`` if the character has been identified as a "mirrored"
|
|
character in bidirectional text, ``0`` otherwise.
|
|
|
|
|
|
.. function:: decomposition(chr)
|
|
|
|
Returns the character decomposition mapping assigned to the character
|
|
*chr* as string. An empty string is returned in case no such mapping is
|
|
defined.
|
|
|
|
|
|
.. function:: normalize(form, unistr)
|
|
|
|
Return the normal form *form* for the Unicode string *unistr*. Valid values for
|
|
*form* are 'NFC', 'NFKC', 'NFD', and 'NFKD'.
|
|
|
|
The Unicode standard defines various normalization forms of a Unicode string,
|
|
based on the definition of canonical equivalence and compatibility equivalence.
|
|
In Unicode, several characters can be expressed in various way. For example, the
|
|
character U+00C7 (LATIN CAPITAL LETTER C WITH CEDILLA) can also be expressed as
|
|
the sequence U+0043 (LATIN CAPITAL LETTER C) U+0327 (COMBINING CEDILLA).
|
|
|
|
For each character, there are two normal forms: normal form C and normal form D.
|
|
Normal form D (NFD) is also known as canonical decomposition, and translates
|
|
each character into its decomposed form. Normal form C (NFC) first applies a
|
|
canonical decomposition, then composes pre-combined characters again.
|
|
|
|
In addition to these two forms, there are two additional normal forms based on
|
|
compatibility equivalence. In Unicode, certain characters are supported which
|
|
normally would be unified with other characters. For example, U+2160 (ROMAN
|
|
NUMERAL ONE) is really the same thing as U+0049 (LATIN CAPITAL LETTER I).
|
|
However, it is supported in Unicode for compatibility with existing character
|
|
sets (e.g. gb2312).
|
|
|
|
The normal form KD (NFKD) will apply the compatibility decomposition, i.e.
|
|
replace all compatibility characters with their equivalents. The normal form KC
|
|
(NFKC) first applies the compatibility decomposition, followed by the canonical
|
|
composition.
|
|
|
|
Even if two unicode strings are normalized and look the same to
|
|
a human reader, if one has combining characters and the other
|
|
doesn't, they may not compare equal.
|
|
|
|
|
|
In addition, the module exposes the following constant:
|
|
|
|
.. data:: unidata_version
|
|
|
|
The version of the Unicode database used in this module.
|
|
|
|
|
|
.. data:: ucd_3_2_0
|
|
|
|
This is an object that has the same methods as the entire module, but uses the
|
|
Unicode database version 3.2 instead, for applications that require this
|
|
specific version of the Unicode database (such as IDNA).
|
|
|
|
Examples:
|
|
|
|
>>> import unicodedata
|
|
>>> unicodedata.lookup('LEFT CURLY BRACKET')
|
|
'{'
|
|
>>> unicodedata.name('/')
|
|
'SOLIDUS'
|
|
>>> unicodedata.decimal('9')
|
|
9
|
|
>>> unicodedata.decimal('a')
|
|
Traceback (most recent call last):
|
|
File "<stdin>", line 1, in ?
|
|
ValueError: not a decimal
|
|
>>> unicodedata.category('A') # 'L'etter, 'u'ppercase
|
|
'Lu'
|
|
>>> unicodedata.bidirectional('\u0660') # 'A'rabic, 'N'umber
|
|
'AN'
|
|
|
|
|
|
.. rubric:: Footnotes
|
|
|
|
.. [#] http://www.unicode.org/Public/8.0.0/ucd/NameAliases.txt
|
|
|
|
.. [#] http://www.unicode.org/Public/8.0.0/ucd/NamedSequences.txt
|