


In the previous article "How does PHP change a substring of a certain length into a * sign", we introduced string replacement, a method of replacing a substring of a certain length into a * sign, this This time we continue to understand strings and introduce the method of calculating the length of Chinese strings or the length of mixed Chinese and English strings.
How to calculate the length of Chinese string? Regarding this problem, our first reaction may be to use the strlen() function, but the strlen() function is good at processing all-English strings, but it does not work when it comes to mixed Chinese and English strings or pure Chinese strings. Let’s take a look at the following example:
<?php header("Content-type:text/html;charset=utf-8"); //设置字符编码为utf-8 $str = "欢迎来到PHP中文网!"; echo '字符串 “'.$str.'” 的长度为:'.strlen($str).'<br>'; ?>
The output result is:
It can be seen that the strlen() function cannot be accurate due to different rules for processing characters. Returns the length of mixed Chinese and English or pure Chinese strings. So why does it return 27?
That’s because the character encoding we use is utf-8, and a Chinese character occupies three bytes under UTF-8 encoding.
strlen() function In ASCII code, one Chinese character occupies two bytes of space; in UTF-8 encoding, one Chinese character (including traditional Chinese) is equal to three bytes; in Unicode Under encoding, one Chinese character (including traditional Chinese) is equal to two bytes.
In the above example, one of the strings "Welcome to the PHP Chinese website!
" contains 8 Chinese characters and 3 English characters, then 8 *3 3=27
bytes, then the string length is 27.
But such a string length is not what we want. How to deal with Chinese characters and accurately calculate the length of the mixed Chinese and English or pure Chinese string we want?
PHP provides a function to solve this problem, that is the mb_strlen() function.
Still the previous example, this time using the mb_strlen() function to calculate the string length:
<?php header("Content-type:text/html;charset=utf-8"); $str = "欢迎来到PHP中文网!"; echo '字符串 “'.$str.'” 的长度为:'.mb_strlen($str,'utf-8').'<br>'; ?>
The output result is:
It can be seen that in the string $str
, there are 11 Chinese and English exclamation marks, and the output result is also 11. By the way, I found the right person~
mb_strlen() function, whether it is Chinese characters or English, numbers, decimal points, underlines and spaces, only takes up one byte.
Let’s take a brief look at the mb_strlen() function.
mb_strlen($string,$encoding)
The function can return the corresponding number of characters by setting the character encoding; this function accepts a required parameter $string (the string that needs to be detected) and a The omitted parameter $encoding
(character encoding), if omitted, the internal character encoding is used.
We can handle the length problem of Chinese strings well by setting the corresponding $encoding
parameters.
Okay, that’s all. If you want to know anything else, you can click this. → →php video tutorial
Finally, I recommend reading a classic course "PHP String Processing (Jade Girl Heart Sutra Edition)", it's free~ come and learn !
The above is the detailed content of PHP string learning how to return the length of Chinese characters or mixed characters. For more information, please follow other related articles on the PHP Chinese website!

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

Dreamweaver Mac version
Visual web development tools

Notepad++7.3.1
Easy-to-use and free code editor

VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft
