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

Descrizione

Stile procedurale

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.

Elenco dei parametri

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.

Valori restituiti

A string starting at offset offset and ending on a default grapheme cluster boundary that conforms to the size and type specified, o false in caso di fallimento.

Log delle modifiche

Versione Descrizione
7.1.0 Support for negative offsets has been added.

Esempi

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));

?>

Il precedente esempio visualizzerà:

o%CC%88
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User Contributed Notes 3 notes

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5
AJH
14 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 $maxbytes bytes!\n";// Should print: 7 UTF8 characters in a string of 14 bytes!?>
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1
Philo
1 year ago
The other comments on this page were helpful for me.However, consider using something better than empty($value) when checking the value returned by grapheme_extract since it could as well return something like "0" (which of course evaluates to false).
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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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