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grapheme_extract

(PHP 5 >= 5.3.0, 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.

说明

过程化风格

string grapheme_extract ( string $haystack , int $size [, int $extract_type [, int $start = 0 [, int &$next ]]] )

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

参数

haystack

String to search.

size

Maximum number items - based on the $extract_type - to return.

extract_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.
start

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. If $start 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.

返回值

A string starting at offset $start and ending on a default grapheme cluster boundary that conforms to the $size and $extract_type specified.

范例

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 ));

?>

以上例程会输出:

1

o%CC%88

参见

  • grapheme_substr() - Return part of a string
  • »  Unicode Text Segmentation: Grapheme Cluster Boundaries

用户评论:

[#1] AJH [2011-07-12 16:37:58]

Here's how to use grapheme_extract() to loop across a UTF-8 string character by character.

<?php

$str 
"?abc?????";
// 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;
        
$c grapheme_extract($str1GRAPHEME_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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