How to find the number of occurrences of a specified character in a php string

Two ways to find the number of times: 1. Use the substr_count() function to count the number of times English and Chinese characters appear in a string in a case-sensitive manner. The syntax "substr_count(string, specified character, start Search position, search length)". 2. Use the mb_substr_count() function to count the number of times English characters or Chinese characters appear in a string in a case-sensitive manner. The syntax is "mb_substr_count(string, specified character, character encoding)".

The operating environment of this tutorial: windows7 system, PHP version 8.1, DELL G3 computer

How to find specified characters in a php string The number of occurrences? PHP provides two functions to achieve this:

• substr_count()

• mb_substr_count()

Both functions can count the number of times a substring (English and Chinese characters) appears in a string (case-sensitive); but the mb_substr_count() function can set the character encoding.

Method 1: Use the substr_count() function to find the number of occurrences of a specified character

The substr_count() function counts the number of times English and Chinese characters appear in a string.

substr_count(string,substring,start,length)

• string Required. Specifies the string to be checked.
  

• substring Required. Specifies the string to search for.

• start Optional. Specifies where in the string to begin the search.

• length Optional. Specifies the length of the search.

Example:

<?php
header("Content-type:text/html;charset=utf-8");
$str="16abcdDcbasA76";
echo $str."<br><br>";
$count=substr_count($str,"a");
echo "字符a 出现了：".$count."次";
?>

Method 2: Use the mb_substr_count() function to find the number of occurrences of a specified character

mb_substr_count() function counts the number of times English and Chinese characters appear in a string (character encoding can be set).

mb_substr_count(string,substring,encoding)

• string Required. Specifies the string to be checked.

• substring Required. Specifies the string to search for.

• encoding Optional. Specifies the character encoding. If omitted or null, the internal character encoding is used.

Example:

<?php
header("Content-type:text/html;charset=utf-8");
$str="我爱上海。上海是中国最大的城市。";
echo $str."<br><br>";
$count=mb_substr_count($str,"上海");
echo "上海 出现了：".$count."次";
?>

<?php
header("Content-type:text/html;charset=utf-8");
$str="16abcdDcbasA76";
echo $str."<br><br>";
$count=mb_substr_count($str,"A");
echo "字符A 出现了：".$count."次";
?>

Recommended learning: "PHP video tutorial 》

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