iconv_strlen()

(PHP 5, PHP 7)

返回字符串的字符数统计

说明

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

和 strlen() 不同的是，iconv_strlen() 统计了给定的字节序列$str中出现字符数的统计，基于指定的字符集，其产生的结果不一定和字符字节数相等。

参数

$str

该字符串。

$charset

如果省略了$charset参数，假设$str的编码为 iconv.internal_encoding。

返回值

返回$str字符数的统计，是整型。

参见

• grapheme_strlen()Get string length in grapheme units
• mb_strlen()获取字符串的长度
• strlen()获取字符串长度

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
$str = "$str = "I\1ërnâtiôn\xe9àlizætiøn";";
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