How to determine how many characters a string contains in php

php method to determine how many characters a string contains: 1. Use strlen() function, syntax "strlen($string)"; 2. Use mb_strlen() function, syntax "mb_strlen($string, ' Character Encoding')".

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

php determines the string Contains several characters

In PHP, determining how many characters a string contains is to determine the length of the string.

There are two functions commonly used in PHP to calculate the length of a string, namely the strlen() and mb_strlen() functions. When processing all-English strings, the effect of these two functions is the same, but when processing mixed Chinese and English strings or pure Chinese strings, these two functions will have some differences.

1. strlen() function

strlen() function can return the length of a given string. Its syntax is as follows:

strlen($string)

Parameters $string is the string whose length needs to be calculated. Returns 0 if $string is empty.

Note: In the strlen() function, numbers, English, decimal points, underscores and spaces occupy one character length; while a GB2312 encoded Chinese character occupies two characters in length, and a UTF-8 encoded Chinese character occupies a length of one character. Chinese characters are three characters long.

Example:

<?php
header("Content-type:text/html;charset=utf-8");
$str2 = &#39;hello&#39;;
echo strlen($str2), &#39;<br>&#39;; //5
$str3 = &#39;中国&#39;;
echo strlen($str3), &#39;<br>&#39;; //6
$str4 = &#39;&#39;;
echo strlen($str4), &#39;<br>&#39;; //0
?>

#2, mb_strlen() function

mb_strlen() function is the same The length of the string can be returned. The syntax format is as follows:

mb_strlen($str [, $encoding = mb_internal_encoding()])

Among them, $str is the string whose length needs to be calculated, $encoding is an optional parameter, which is the character encoding. If omitted, the internal character encoding is used.

The return value of the mb_strlen() function is the number of characters contained in the string $str with $encoding encoding. If $encoding is invalid, false is returned.

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:

<?php
header("Content-type:text/html;charset=gdk");
$str1 = &#39;hello&#39;; 
echo mb_strlen($str1), &#39;<br>&#39;; //5
$str2 = &#39;你好中国&#39;;
echo mb_strlen($str2, &#39;utf-8&#39;), &#39;<br>&#39;; //4

$str3 = &#39;你好中国&#39;;
echo strlen($str3), &#39;<br>&#39;; //12
?>

Recommended learning: "PHP Video Tutorial"

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