grapheme_extract

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

grapheme_extractFunction 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 2 notes

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4
AJH
12 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
0
yevgen dot grytsay at gmail dot com
3 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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