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grapheme_extract

PHP function Edit on GitHub ✎

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

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

Description

Procedural

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.

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, Falseforfailure.

Changelog

Version	Description
7.1.0	Support for negative `offset`s has been added.

Examples

grapheme_extract() example

php

<?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:

output

o%CC%88