mb_str_split

(PHP 7 >= 7.4.0, PHP 8)

mb_str_split — Given a multibyte string, return an array of its characters

说明

mb_str_split ( string $string , int $length = 1 , string|null $encoding = null ) : array

This function will return an array of strings, it is a version of str_split() with support for encodings of variable character size as well as fixed-size encodings of 1,2 or 4 byte characters. If the length parameter is specified, the string is broken down into chunks of the specified length in characters (not bytes). The encoding parameter can be optionally specified and it is good practice to do so.

参数

string

The string to split into characters or chunks.

length

If specified, each element of the returned array will be composed of multiple characters instead of a single character.

encoding

encoding 参数为字符编码。如果省略或是 null，则使用内部字符编码。

A string specifying one of the supported encodings.

返回值

mb_str_split() returns an array of strings.

更新日志

版本 说明
8.0.0 现在 encoding 可以为 null。
8.0.0 This function no longer returns false on failure.

参见

User Contributed Notes

vovan-ve at yandex dot ru 25-Oct-2020 05:48
Lazy polyfill for UTF-8 only:

function utf8_str_split(string $input, int $splitLength = 1)
{
    $re = \sprintf('/\\G.{1,%d}+/us', $splitLength);
    \preg_match_all($re, $input, $m);
    return $m[0];
}
info at ensostudio dot ru 11-Oct-2020 11:04
Note: function return NULL if can't convert argument type.

Polyfill PHP < 7.4 based on package "symfony/polyfill-mbstring":
<?php
function mb_str_split($string, $split_length = 1, $encoding = null)
{
    if (null !== $string && !\is_scalar($string) && !(\is_object($string) && \method_exists($string, '__toString'))) {
        trigger_error('mb_str_split(): expects parameter 1 to be string, '.\gettype($string).' given', E_USER_WARNING);
        return null;
    }
    if (null !== $split_length && !\is_bool($split_length) && !\is_numeric($split_length)) {
        trigger_error('mb_str_split(): expects parameter 2 to be int, '.\gettype($split_length).' given', E_USER_WARNING);
        return null;
    }
    $split_length = (int) $split_length;
    if (1 > $split_length) {
        trigger_error('mb_str_split(): The length of each segment must be greater than zero', E_USER_WARNING);
        return false;
    }
    if (null === $encoding) {
        $encoding = mb_internal_encoding();
    } else {
        $encoding = (string) $encoding;
    }
   
    if (! in_array($encoding, mb_list_encodings(), true)) {
        static $aliases;
        if ($aliases === null) {
            $aliases = [];
            foreach (mb_list_encodings() as $encoding) {
                $encoding_aliases = mb_encoding_aliases($encoding);
                if ($encoding_aliases) {
                    foreach ($encoding_aliases as $alias) {
                        $aliases[] = $alias;
                    }
                }
            }
        }
        if (! in_array($encoding, $aliases, true)) {
            trigger_error('mb_str_split(): Unknown encoding "'.$encoding.'"', E_USER_WARNING);
            return null;
        }
    }
   
    $result = [];
    $length = mb_strlen($string, $encoding);
    for ($i = 0; $i < $length; $i += $split_length) {
        $result[] = mb_substr($string, $i, $split_length, $encoding);
    }
    return $result;
}
?>