PHPstrlen () and mb

Strlen-get string Length description intstrlen (string $ string) returns the length of the given string. The length of the string parameter. If the return value is successful, the length of the string is returned. If the return value is null, the return value is 0. Mb_strlen-get the length description of the string mixedmb

Strlen-get string Length description int strlen (string $ string) returns the length of the given string. The length of the string parameter. If the return value is successful, the length of the string is returned. If the return value is null, the return value is 0. Mb_strlen-get the length description of the string mixed mb

Strlen-get the string length

Description

IntStrlen(String$string)

Returns the given string.string.

Parameters

stringThe string to be calculated.

Return Value

Returns a string.stringLength; ifstringIf it is null, 0 is returned.

Mb_strlen-get the string length

Description

MixedMb_strlen(String$str[, String$encoding= Mb_internal_encoding ()])

Returns the length of a string.

Parameters

strThe string to be checked.

encoding encodingThe parameter is character encoding. If omitted, internal character encoding is used.

Return Value

ReturnsencodingEncoded stringstrThe number of characters. Multi-byte characters are counted as 1.

IfencodingInvalidFALSE.

The above is the explanation of the two functions in the manual. At first glance, it seems that they are similar.

The following example describes the differences between the two.

// The file encoding method is UTF8 $ str = 'character a, string B, 2 degrees long '; echo strlen ($ str ).'
'; // 19 echo mb_strlen ($ str, 'utf-8 ').'
'; // 9

Let's look at the next example.

 '; // 14 echo mb_strlen ($ str, 'utf-8 ').'
'; // 9?>

Result Analysis: When the strlen character length is reached, the Chinese character of UTF8 is counted as three characters in length,

Therefore, the length of "word a character 1 string B length 2 degrees" is 3 + 1 + 3 + 1 + 3 + 1 + 3 + 1 + 3 = 19,

When mb_strlen is calculated, if the selected inner code is UTF8, a Chinese character is regarded as 1 in length. Therefore, the length of "character a, string B, length 2 degrees" is 9.

In gb2312, when strlen calculates the character length, a Chinese character is counted as two characters.

In addition, it should be noted that mb_strlen is not a PHP core function. before using it, make sure to load php_mbstring.dll in php. ini; otherwise, the number of undefined functions may occur.