(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
Procedural style
$haystack,$size,$type =GRAPHEME_EXTR_COUNT,$offset = 0,&$next =nullFunction to extract a sequence of default grapheme clusters from a text buffer, which must be encoded in UTF-8.
haystackString to search.
size Maximum number items - based on thetype - to return.
type Defines the type of units referred to by thesize parameter:
size is the number of default grapheme clusters to extract.size is the maximum number of bytes returned.size is the maximum number of UTF-8 characters returned.offset Starting position inhaystack in bytes - if given, it must be zero or a positive value that is less than or equal to the length ofhaystack in bytes, or a negative value that counts from the end ofhaystack. Ifoffset does not point to the first byte of a UTF-8 character, the start position is moved to the next character boundary.
nextReference 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.
A string starting at offsetoffset and ending on a default grapheme cluster boundary that conforms to thesize andtype specified, orfalse on failure.
| Version | Description |
|---|---|
| 7.1.0 | Support for negativeoffsets has been added. |
Example #1grapheme_extract() example
<?php
$char_a_ring_nfd="a\xCC\x8A";// 'LATIN SMALL LETTER A WITH RING ABOVE' (U+00E5) normalization form "D"
$char_o_diaeresis_nfd="o\xCC\x88";// 'LATIN SMALL LETTER O WITH DIAERESIS' (U+00F6) normalization form "D"
printurlencode(grapheme_extract($char_a_ring_nfd.$char_o_diaeresis_nfd,1,GRAPHEME_EXTR_COUNT,2));
?>The above example will output:
o%CC%88
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$maxbytes bytes!\n";
// Should print: 7 UTF8 characters in a string of 14 bytes!
?>The other comments on this page were helpful for me.
However, consider using something better than empty($value) when checking the value returned by grapheme_extract since it could as well return something like "0" (which of course evaluates to false).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
?>