1 2 :mod:`unicodedata` --- Unicode Database 3 ======================================= 4 5 .. module:: unicodedata 6 :synopsis: Access the Unicode Database. 7 .. moduleauthor:: Marc-Andre Lemburg <mal (a] lemburg.com> 8 .. sectionauthor:: Marc-Andre Lemburg <mal (a] lemburg.com> 9 .. sectionauthor:: Martin v. Lwis <martin (a] v.loewis.de> 10 11 12 .. index:: 13 single: Unicode 14 single: character 15 pair: Unicode; database 16 17 This module provides access to the Unicode Character Database which defines 18 character properties for all Unicode characters. The data in this database is 19 based on the :file:`UnicodeData.txt` file version 5.2.0 which is publicly 20 available from ftp://ftp.unicode.org/. 21 22 The module uses the same names and symbols as defined by the UnicodeData File 23 Format 5.2.0 (see http://www.unicode.org/reports/tr44/tr44-4.html). 24 It defines the following functions: 25 26 27 .. function:: lookup(name) 28 29 Look up character by name. If a character with the given name is found, return 30 the corresponding Unicode character. If not found, :exc:`KeyError` is raised. 31 32 33 .. function:: name(unichr[, default]) 34 35 Returns the name assigned to the Unicode character *unichr* as a string. If no 36 name is defined, *default* is returned, or, if not given, :exc:`ValueError` is 37 raised. 38 39 40 .. function:: decimal(unichr[, default]) 41 42 Returns the decimal value assigned to the Unicode character *unichr* as integer. 43 If no such value is defined, *default* is returned, or, if not given, 44 :exc:`ValueError` is raised. 45 46 47 .. function:: digit(unichr[, default]) 48 49 Returns the digit value assigned to the Unicode character *unichr* as integer. 50 If no such value is defined, *default* is returned, or, if not given, 51 :exc:`ValueError` is raised. 52 53 54 .. function:: numeric(unichr[, default]) 55 56 Returns the numeric value assigned to the Unicode character *unichr* as float. 57 If no such value is defined, *default* is returned, or, if not given, 58 :exc:`ValueError` is raised. 59 60 61 .. function:: category(unichr) 62 63 Returns the general category assigned to the Unicode character *unichr* as 64 string. 65 66 67 .. function:: bidirectional(unichr) 68 69 Returns the bidirectional class assigned to the Unicode character *unichr* as 70 string. If no such value is defined, an empty string is returned. 71 72 73 .. function:: combining(unichr) 74 75 Returns the canonical combining class assigned to the Unicode character *unichr* 76 as integer. Returns ``0`` if no combining class is defined. 77 78 79 .. function:: east_asian_width(unichr) 80 81 Returns the east asian width assigned to the Unicode character *unichr* as 82 string. 83 84 .. versionadded:: 2.4 85 86 87 .. function:: mirrored(unichr) 88 89 Returns the mirrored property assigned to the Unicode character *unichr* as 90 integer. Returns ``1`` if the character has been identified as a "mirrored" 91 character in bidirectional text, ``0`` otherwise. 92 93 94 .. function:: decomposition(unichr) 95 96 Returns the character decomposition mapping assigned to the Unicode character 97 *unichr* as string. An empty string is returned in case no such mapping is 98 defined. 99 100 101 .. function:: normalize(form, unistr) 102 103 Return the normal form *form* for the Unicode string *unistr*. Valid values for 104 *form* are 'NFC', 'NFKC', 'NFD', and 'NFKD'. 105 106 The Unicode standard defines various normalization forms of a Unicode string, 107 based on the definition of canonical equivalence and compatibility equivalence. 108 In Unicode, several characters can be expressed in various way. For example, the 109 character U+00C7 (LATIN CAPITAL LETTER C WITH CEDILLA) can also be expressed as 110 the sequence U+0043 (LATIN CAPITAL LETTER C) U+0327 (COMBINING CEDILLA). 111 112 For each character, there are two normal forms: normal form C and normal form D. 113 Normal form D (NFD) is also known as canonical decomposition, and translates 114 each character into its decomposed form. Normal form C (NFC) first applies a 115 canonical decomposition, then composes pre-combined characters again. 116 117 In addition to these two forms, there are two additional normal forms based on 118 compatibility equivalence. In Unicode, certain characters are supported which 119 normally would be unified with other characters. For example, U+2160 (ROMAN 120 NUMERAL ONE) is really the same thing as U+0049 (LATIN CAPITAL LETTER I). 121 However, it is supported in Unicode for compatibility with existing character 122 sets (e.g. gb2312). 123 124 The normal form KD (NFKD) will apply the compatibility decomposition, i.e. 125 replace all compatibility characters with their equivalents. The normal form KC 126 (NFKC) first applies the compatibility decomposition, followed by the canonical 127 composition. 128 129 Even if two unicode strings are normalized and look the same to 130 a human reader, if one has combining characters and the other 131 doesn't, they may not compare equal. 132 133 .. versionadded:: 2.3 134 135 In addition, the module exposes the following constant: 136 137 138 .. data:: unidata_version 139 140 The version of the Unicode database used in this module. 141 142 .. versionadded:: 2.3 143 144 145 .. data:: ucd_3_2_0 146 147 This is an object that has the same methods as the entire module, but uses the 148 Unicode database version 3.2 instead, for applications that require this 149 specific version of the Unicode database (such as IDNA). 150 151 .. versionadded:: 2.5 152 153 Examples: 154 155 >>> import unicodedata 156 >>> unicodedata.lookup('LEFT CURLY BRACKET') 157 u'{' 158 >>> unicodedata.name(u'/') 159 'SOLIDUS' 160 >>> unicodedata.decimal(u'9') 161 9 162 >>> unicodedata.decimal(u'a') 163 Traceback (most recent call last): 164 File "<stdin>", line 1, in ? 165 ValueError: not a decimal 166 >>> unicodedata.category(u'A') # 'L'etter, 'u'ppercase 167 'Lu' 168 >>> unicodedata.bidirectional(u'\u0660') # 'A'rabic, 'N'umber 169 'AN' 170 171
