php has two functions to find the length of a string: 1. The strlen() function can calculate the length of an English string, and the syntax is "strlen($string)"; 2. The mb_strlen() function can By setting the character encoding, calculate the length of an English string, a Chinese string, or a mixed Chinese-English string. The syntax is "mb_strlen($string,"Character encoding")".
The operating environment of this tutorial: Windows 7 system, PHP version 8.1, DELL G3 computer
Commonly used in PHP to calculate the length of a string There are two functions, namely strlen() and mb_strlen() functions. When processing all-English strings, the effects of these two functions are the same. However, when processing mixed Chinese and English strings or pure Chinese strings, these two functions will have some differences:
- # The ##strlen() function can calculate the length of English strings, but for mixed Chinese and English or pure Chinese strings, the length cannot be accurately calculated.
- mb_strlen() function can calculate the length of English strings, Chinese strings or mixed Chinese and English strings.
1. strlen() function finds the length of a string
strlen() function can return the length of a given string, its syntax format As follows:strlen($string)
- The parameter $string is the string whose length needs to be calculated. Returns 0 if $string is empty.
Note: In the strlen() function, numbers, English, decimal point, underline and space occupy one character; while a GB2312 encoded Chinese character occupies two characters. A UTF-8 encoded Chinese character is three characters long.Example:
<?php header("Content-type:text/html;charset=utf-8"); $str = "hello world!"; echo '字符串 “'.$str.'” 的长度为:'.strlen($str).'<br>'; ?>$str string contains 10 English letters, 1 space and 1 English exclamation mark, a total of 12 characters, so the output length is 12.
<?php header("Content-type:text/html;charset=utf-8"); $str = "hello 你好!"; echo '字符串 “'.$str.'” 的长度为:'.strlen($str).'<br>'; ?>
2. mb_strlen() function finds the length of a string
mb_strlen() function can also return the length of a string. The syntax format is as follows:mb_strlen($str [, $encoding = mb_internal_encoding()])
- $str is the string whose length needs to be calculated
- $encoding is an optional parameter, which is the character encoding. If If omitted, the internal character encoding is used.
Note: Unlike the strlen() function, in the mb_strlen() function, whether it is Chinese characters, English, numbers, decimal points, underscores and spaces, they only occupy one character in length.[Example] Use the mb_strlen() function to get the string length.
<?php header("Content-type:text/html;charset=utf-8"); $str = "hello 你好!"; echo '字符串 “'.$str.'” 的长度为:'.mb_strlen($str,"utf-8").'<br>'; $str = "欢迎来到PHP中文网!"; echo '<br>字符串 “'.$str.'” 的长度为:'.mb_strlen($str,'utf-8').'<br>'; ?>
$encoding parameters.
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