iconv 函数
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iconv_strlen

(PHP 5)

iconv_strlen — Returns the character count of string

说明

int iconv_strlen ( string $str [, string $charset = ini_get("iconv.internal_encoding") ] )

In contrast to strlen(), iconv_strlen() counts the occurrences of characters in the given byte sequence str on the basis of the specified character set, the result of which is not necessarily identical to the length of the string in byte.

参数

str

The string.

charset

If charset parameter is omitted, str is assumed to be encoded in iconv.internal_encoding.

返回值

Returns the character count of str, as an integer.

参见

iconv 函数
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PHP手册
PHP手册 - N: Returns the character count of string

用户评论:

hfuecks @ nospam org (25-Feb-2006 12:58)

If iconv_strlen is passed a UTF-8 string containing badly formed sequences, it will return FALSE. This is in contrast to mb_strlen of the behaviour of utf8_decode, which strip out any bad sequences;

<?php
# UTF-8 string containing bad sequence: \xe9
$str = "Itrntin\xe9liztin";

print "mb_strlen: ".mb_strlen($str,'UTF-8')."\n";
print "strlen/utf8_decode: ".strlen(utf8_decode($str))."\n";
print "iconv_strlen: ".iconv_strlen($str,'UTF-8')."\n";
?>

Displays;

mb_strlen: 20
strlen/utf8_decode: 20
iconv_strlen:

(PHP 5.0.5)

As such it is being "stricter" than mb_strlen and it may mean you need to check for invalid sequences first. A quick way to check is to exploit the behaviour of the PCRE extension (see notes on pattern modifiers);

<?php
if (preg_match('/^.{1}/us',$str,$ar) != 1) {
    die("string contains invalid UTF-8");
}
?>

A slower but stricter check (regex) can be found at: http://www.w3.org/International/questions/qa-forms-utf-8

Similiar applies to iconv_substr, iconv_strpos and iconv_strrpos