PHP 7.0.6 Released

    Unicode character properties

    Since 5.1.0, three additional escape sequences to match generic character types are available when UTF-8 mode is selected. They are:

    \p{xx}
    a character with the xx property
    \P{xx}
    a character without the xx property
    \X
    an extended Unicode sequence

    The property names represented by xx above are limited to the Unicode general category properties. Each character has exactly one such property, specified by a two-letter abbreviation. For compatibility with Perl, negation can be specified by including a circumflex between the opening brace and the property name. For example, \p{^Lu} is the same as \P{Lu}.

    If only one letter is specified with \p or \P, it includes all the properties that start with that letter. In this case, in the absence of negation, the curly brackets in the escape sequence are optional; these two examples have the same effect: 

    \p{L}
\pL
    Supported property codes
    Property Matches Notes
    C Other  
    Cc Control  
    Cf Format  
    Cn Unassigned  
    Co Private use  
    Cs Surrogate  
    L Letter Includes the following properties: Ll, Lm, Lo, Lt and Lu.
    Ll Lower case letter  
    Lm Modifier letter  
    Lo Other letter  
    Lt Title case letter  
    Lu Upper case letter  
    M Mark  
    Mc Spacing mark  
    Me Enclosing mark  
    Mn Non-spacing mark  
    N Number  
    Nd Decimal number  
    Nl Letter number  
    No Other number  
    P Punctuation  
    Pc Connector punctuation  
    Pd Dash punctuation  
    Pe Close punctuation  
    Pf Final punctuation  
    Pi Initial punctuation  
    Po Other punctuation  
    Ps Open punctuation  
    S Symbol  
    Sc Currency symbol  
    Sk Modifier symbol  
    Sm Mathematical symbol  
    So Other symbol  
    Z Separator  
    Zl Line separator  
    Zp Paragraph separator  
    Zs Space separator  

    Extended properties such as InMusicalSymbols are not supported by PCRE.

    Specifying case-insensitive (caseless) matching does not affect these escape sequences. For example, \p{Lu} always matches only upper case letters.

    Sets of Unicode characters are defined as belonging to certain scripts. A character from one of these sets can be matched using a script name. For example:

    • \p{Greek}
    • \P{Han}

    Those that are not part of an identified script are lumped together as Common. The current list of scripts is:

    Supported scripts
    Arabic Armenian Avestan Balinese Bamum
    Batak Bengali Bopomofo Brahmi Braille
    Buginese Buhid Canadian_Aboriginal Carian Chakma
    Cham Cherokee Common Coptic Cuneiform
    Cypriot Cyrillic Deseret Devanagari Egyptian_Hieroglyphs
    Ethiopic Georgian Glagolitic Gothic Greek
    Gujarati Gurmukhi Han Hangul Hanunoo
    Hebrew Hiragana Imperial_Aramaic Inherited Inscriptional_Pahlavi
    Inscriptional_Parthian Javanese Kaithi Kannada Katakana
    Kayah_Li Kharoshthi Khmer Lao Latin
    Lepcha Limbu Linear_B Lisu Lycian
    Lydian Malayalam Mandaic Meetei_Mayek Meroitic_Cursive
    Meroitic_Hieroglyphs Miao Mongolian Myanmar New_Tai_Lue
    Nko Ogham Old_Italic Old_Persian Old_South_Arabian
    Old_Turkic Ol_Chiki Oriya Osmanya Phags_Pa
    Phoenician Rejang Runic Samaritan Saurashtra
    Sharada Shavian Sinhala Sora_Sompeng Sundanese
    Syloti_Nagri Syriac Tagalog Tagbanwa Tai_Le
    Tai_Tham Tai_Viet Takri Tamil Telugu
    Thaana Thai Tibetan Tifinagh Ugaritic
    Vai Yi        

    The \X escape matches a Unicode extended grapheme cluster. An extended grapheme cluster is one or more Unicode characters that combine to form a single glyph. In effect, this can be thought of as the Unicode equivalent of . as it will match one composed character, regardless of how many individual characters are actually used to render it.

    In versions of PCRE older than 8.32 (which corresponds to PHP versions before 5.4.14 when using the bundled PCRE library), \X is equivalent to (?>\PM\pM*). That is, it matches a character without the "mark" property, followed by zero or more characters with the "mark" property, and treats the sequence as an atomic group (see below). Characters with the "mark" property are typically accents that affect the preceding character.

    Matching characters by Unicode property is not fast, because PCRE has to search a structure that contains data for over fifteen thousand characters. That is why the traditional escape sequences such as \d and \w do not use Unicode properties in PCRE.

    User Contributed Notes

    xuantoaiph at gmail dot com
    2 years ago
    My country, Vietnam, have our own alphabet table:
    http://en.wikipedia.org/wiki/Vietnamese_alphabet
    I hope PHP will support better than in Vietnamese.
    mercury at caucasus dot net
    5 years ago
    An excellent article explaining all these properties can be found here: http://www.regular-expressions.info/unicode.html
    Yzmir Ramirez
    2 years ago
    If you are working with older environments you will need to first check to see if the version of PCRE will work with unicode directives described above:

    <?php

    // Need to check PCRE version because some environments are
    // running older versions of the PCRE library
    // (run in *nix environment `pcretest -C`)

    $allowInternational = false;
    if (    defined('PCRE_VERSION')) {
        if (    intval(PCRE_VERSION) >= 7) { // constant available since PHP 5.2.4
                $allowInternational = true;
        }
    }
    ?>

    Now you can do a fallback regex (e.g. use "/[a-z]/i"), when the PCRE library version is too old or not available.
    o_shes01 at uni-muenster dot de
    5 years ago
    For those who wonder: 'letter_titlecase' applies to digraphs/trigraphs, where capitalization involves only the first letter.
    For example, there are three codepoints for the "LJ" digraph in Unicode:
      (*) uppercase "LJ": U+01C7
      (*) titlecase "Lj": U+01C8
      (*) lowercase "lj": U+01C9
    suit at rebell dot at
    6 years ago
    these properties are usualy only available if PCRE is compiled with "--enable-unicode-properties"

    if you want to match any word but want to provide a fallback, you can do something like that:

    <?php
    if(@preg_match_all('/\p{L}+/u', $str, $arr) {
          // fallback goes here
      // for example just '/\w+/u' for a less acurate match
    }
    ?>
    huhwatnouDONTspamPLEASE at hotmail dot com
    3 months ago
    To select UTF-8 mode for the additional escape sequences (\p{xx}, \P{xx}, and \X) , use the "u" modifier (see http://php.net/manual/en/reference.pcre.pattern.modifiers.php).

    I wondered why a German sharp S (ß) was marked as a control character by \p{Cc} and it took me a while to properly read the first sentence: "Since 5.1.0, three additional escape sequences to match generic character types are available when UTF-8 mode is selected. " :-$ and then to find out how to do so.
    o_shes01 at uni-muenster dot de
    5 years ago
    For those who wonder: 'letter_titlecase' applies to digraphs/trigraphs, where capitalization involves only the first letter.
    For example, there are three codepoints for the "LJ" digraph in Unicode:
      (*) uppercase "LJ": U+01C7
      (*) titlecase "Lj": U+01C8
      (*) lowercase "lj": U+01C9
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