mb_strcut

(PHP 4 >= 4.0.6, PHP 5, PHP 7, PHP 8)

mb_strcut — Get part of string

Опис

mb_strcut(
    string $string,
    int $start,
    ?int $length = null,
    ?string $encoding = null
): string

mb_strcut() extracts a substring from a string similarly to mb_substr(), but operates on bytes instead of characters. If the cut position happens to be between two bytes of a multi-byte character, the cut is performed starting from the first byte of that character. This is also the difference to the substr() function, which would simply cut the string between the bytes and thus result in a malformed byte sequence.

Параметри

string

The string being cut.

start

If start is non-negative, the returned string will start at the start'th byte position in string, counting from zero. For instance, in the string 'abcdef', the byte at position 0 is 'a', the byte at position 2 is 'c', and so forth.

If start is negative, the returned string will start at the start'th byte counting back from the end of string. However, if the magnitude of a negative start is greater than the length of the string, the returned portion will start from the beginning of string.

length

Length in bytes. If omitted or NULL is passed, extract all bytes to the end of the string.

If length is negative, the returned string will end at the length'th byte counting back from the end of string. However, if the magnitude of a negative length is greater than the number of characters after the start position, an empty string will be returned.

encoding

Параметром encoding вказується кодування символів. Якщо він пропущений або null, використається внутрішнє кодування.

Значення, що повертаються

mb_strcut() returns the portion of string specified by the start and length parameters.

Журнал змін

Версія	Опис
8.0.0	`encoding` тепер може бути `null`.

Прогляньте також

mb_substr() - Get part of string
mb_internal_encoding() - Set/Get internal character encoding

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User Contributed Notes 4 notes

down

olivthill at gmail dot com ¶

6 years ago

Here is an example with UTF8 characters, to see how the start and length arguments are working:

  $str_utf8 = utf8_encode("Déjà_vu");
  $str_utf8_0 = mb_strcut($str_utf8, 0, 4, "UTF-8"); // Déj
  $str_utf8_1 = mb_strcut($str_utf8, 1, 4, "UTF-8"); // éj
  $str_utf8_2 = mb_strcut($str_utf8, 2, 4, "UTF-8"); // éj
  $str_utf8_3 = mb_strcut($str_utf8, 3, 4, "UTF-8"); // jà_
  $str_utf8_4 = mb_strcut($str_utf8, 4, 4, "UTF-8"); // à_v

The string includes two special charaters, "é" and "à" internally coded with two bytes.
Note that a multibyte character is removed rather than kept in half at the end of the output.
Note also that the result is the same for a cut 1,4 and a cut 2,4 with this string.

down

t dot starling at physics dot unimelb dot edu dot au ¶

20 years ago

What the manual and the first commenter are trying to say is that mb_strcut uses byte offsets, as opposed to mb_substr which uses character offsets. 

Both mb_strcut and mb_substr appear to treat negative and out-of-range offsets and lengths in the basically the same way as substr. An exception is that if start is too large, an empty string will be returned rather than FALSE. Testing indicates that mb_strcut first works out start and end byte offsets, then moves each offset left to the nearest character boundary.

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David Juhasz ¶

2 years ago

This was driving me crazy, because mb_strcut() kept returning an empty string.  The $length parameter seems to have a max value of 2^32-1 (2147483647).

Works:
<?php
  # output: Полуустав
  echo mb_strcut('Полуустав', 0, pow(2,31)-1);
?>

Doesn't work:
<?php
  # nothing is output
  echo mb_strcut('Полуустав', 0, pow(2,31));
?>

My PHP_INT_MAX value is much larger than 2^32-1, so I'm not sure why larger values for $length don't work. :(

<?php
  # output: 9223372036854775807
  echo PHP_INT_MAX;
?>

down

-1

oyag02 at yahoo dot co dot jp ¶

21 years ago

diffrence between mb_substr and mb_substr

example:
mb_strcut('I_ROHA', 1, 2) returns 'I_'. Treated as byte stream.
mb_substr('I_ROHA', 1, 2) returns 'ROHA' Treated as character stream.

# 'I_' 'RO' 'HA' means multi-byte character

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