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    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

    function 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:

    Caution

    GRAPHEME_EXTR_COUNT limits the number of grapheme clusters (visual units), not the number of bytes. A single grapheme cluster can span many bytes — for example, a family emoji with ZWJ sequences (👨‍👩‍👧‍👦) is one grapheme cluster but 25 bytes. When the extracted string must fit within a byte budget, use GRAPHEME_EXTR_MAXBYTES instead. GRAPHEME_EXTR_MAXBYTES always returns complete grapheme clusters within the byte budget, but returns an empty string if the budget is smaller than the first grapheme cluster.

    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

    See Also

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    User Contributed Notes 3 notes

    up
    5
    AJH
    15 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 $maxbytes bytes!\n";
// Should print: 7 UTF8 characters in a string of 14 bytes!
?>
    up
    1
    Philo
    2 years ago
    The other comments on this page were helpful for me.
However, consider using something better than empty($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
    6 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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