grapheme_extract

    (PHP 5 >= 5.3.0, PHP 7, PHP 8, PECL intl >= 1.0.0)

    grapheme_extract — Function to extract a sequence of default grapheme clusters from a text buffer, which must be encoded in UTF-8

    Description

    Procedural style

    grapheme_extract(
        string $haystack,
        int $size,
        int $type = GRAPHEME_EXTR_COUNT,
        int $offset = 0,
        int &$next = null
    ): string|false

    Function to extract a sequence of default grapheme clusters from a text buffer, which must be encoded in UTF-8.

    Parameters

    haystack

    String to search.

    size

    Maximum number items - based on the type - to return.

    type

    Defines the type of units referred to by the size parameter:

    • GRAPHEME_EXTR_COUNT (default) -size is the number of default grapheme clusters to extract.
    • GRAPHEME_EXTR_MAXBYTES -size is the maximum number of bytes returned.
    • GRAPHEME_EXTR_MAXCHARS - size is the maximum number of UTF-8 characters returned.

    offset

    Starting position in haystack in bytes - if given, it must be zero or a positive value that is less than or equal to the length of haystack in bytes, or a negative value that counts from the end of haystack. If offset does not point to the first byte of a UTF-8 character, the start position is moved to the next character boundary.

    next

    Reference to a value that will be set to the next starting position. When the call returns, this may point to the first byte position past the end of the string.

    Return Values

    A string starting at offset offset and ending on a default grapheme cluster boundary that conforms to the size and type specified, or false on failure.

    Changelog

    Version Description
    7.1.0 Support for negative offsets has been added.

    Examples

    Example #1 grapheme_extract() example

    <?php

    $char_a_ring_nfd     = "a\xCC\x8A"; // 'LATIN SMALL LETTER A WITH RING ABOVE' (U+00E5) normalization form "D"
    $char_o_diaeresis_nfd = "o\xCC\x88"; // 'LATIN SMALL LETTER O WITH DIAERESIS' (U+00F6) normalization form "D"

    print urlencode(grapheme_extract( $char_a_ring_nfd . $char_o_diaeresis_nfd, 1, GRAPHEME_EXTR_COUNT, 2));

    ?>

    The above example will output:

    o%CC%88

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    User Contributed Notes 3 notes

    up
    5
    AJH
    13 years ago
    Here's how to use grapheme_extract() to loop across a UTF-8 string character by character.

    <?php

    $str     = "سabcक’…";
    // if the previous line didn't come through, the string contained:
    //U+0633,U+0061,U+0062,U+0063,U+0915,U+2019,U+2026

    $n = 0;

    for (     $start = 0, $next = 0, $maxbytes = strlen($str), $c = '';
    $start < $maxbytes;
    $c = grapheme_extract($str, 1, GRAPHEME_EXTR_MAXCHARS , ($start = $next), $next)
    )
    {
    if (empty(    $c))
    continue;
    echo     "This utf8 character is " . strlen($c) . " bytes long and its first byte is " . ord($c[0]) . "\n";
    $n++;
    }
    echo     "$n UTF-8 characters in a string of $maxbytes bytes!\n";
    // Should print: 7 UTF8 characters in a string of 14 bytes!
    ?>
    up
    1
    Philo
    1 year ago
    The other comments on this page were helpful for me.
    However, consider using something better than empty($value) when checking the value returned by grapheme_extract since it could as well return something like "0" (which of course evaluates to false).
    up
    1
    yevgen dot grytsay at gmail dot com
    4 years ago
    Looping through grapheme clusters:

    <?php

    // Example taken from Rust documentation: https://doc.rust-lang.org/book/ch08-02-strings.html#bytes-and-scalar-values-and-grapheme-clusters-oh-my
    $str = "नमस्ते";
    // Alternatively:
    //$str = pack('C*', ...[224, 164, 168, 224, 164, 174, 224, 164, 184, 224, 165, 141, 224, 164, 164, 224, 165, 135]);
    $next = 0;
    $maxbytes = strlen($str);

    var_dump($str);

    while (    $next < $maxbytes) {
    $char = grapheme_extract($str, 1, GRAPHEME_EXTR_COUNT, $next, $next);
    if (empty(    $char)) {
    continue;
    }
    echo     "{$char} - This utf8 character is " . strlen($char) . ' bytes long', PHP_EOL;
    }

    //string(18) "नमस्ते"
    //न - This utf8 character is 3 bytes long
    //म - This utf8 character is 3 bytes long
    //स् - This utf8 character is 6 bytes long
    //ते - This utf8 character is 6 bytes long
    ?>
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