How to check if a URL contains a specific string using PHP? (code example)

Basically everything contained in the URL is a string, so how to check whether the URL contains a specific string? This article will give you a brief introduction to how to use PHP to check specific strings in URLs. I hope it will be helpful to you.

There are two ways to check a specific string in the URL: the first way is to find and match substrings in the string, and the second way is to Regular expression to find matches. PHP contains functions to implement these two methods. Let's take a look at PHP's method of checking whether a URL contains a specific string. [Video tutorial recommendation: PHP tutorial]

Method 1: Find and match substrings in the string

strpos() function

The strpos() function is used to find the first occurrence of a substring in a string. The function returns the starting index of the substring if the substring exists, otherwise it returns False if the substring is not found in the string (URL).

Note: The strpos() function is case-sensitive and case-sensitive.

Example: Use strpos() function to find a specific string in a URL.

<?php 
header("content-type:text/html;charset=utf-8");  
// 在URL中查找特定的子字符串
  
// 给定URL
$url = &#39;http://www.php.cn/course/list/29.html&#39;; 
echo &#39;URL为： &#39;.$url.&#39; <br>&#39; ; 
// 搜索子字符串
$key = &#39;php&#39;; 
  
if (strpos($url, $key) == false) { 
    echo &#39;URL中不存在子字符串&#39;.$key.&#39; <br>&#39; ; 
} 
else { 
    echo &#39;URL中存在子字符串 &#39;.$key.&#39; <br>&#39; ; 
} 
  
// 搜索子字符串
$key = &#39;PHP&#39;; 
  
if (strpos($url, $key) == false) { 
    echo &#39;URL中不存在子字符串 &#39;.$key.&#39; <br>&#39; ; 
} 
else { 
    echo &#39;URL中存在子字符串 &#39;.$key.&#39; <br>&#39; ; 
} 
?>

Output:

substr_count() function

substr_count() function is used for calculation The number of times the substring appears in the string. When the number of occurrences of a substring is greater than or equal to 1, it indicates that the URL contains this substring.

Example:

<?php 
header("content-type:text/html;charset=utf-8");   
$url = &#39;http://www.php.cn/course/list/29.html&#39;; 
$key = &#39;php&#39;; 
// 搜索子字符串  
if (substr_count($url, $key) == false) { 
    echo &#39;URL中不存在子字符串&#39;.$key.&#39; <br>&#39; ; 
} 
else { 
    echo &#39;URL中存在子字符串 &#39;.$key.&#39; <br>&#39; ; 
} 
$key = &#39;PHP&#39;; 
  
if (substr_count($url, $key) == false) { 
    echo &#39;URL中不存在子字符串 &#39;.$key.&#39; <br>&#39; ; 
} 
else { 
    echo &#39;URL中存在 &#39;.$key.&#39; <br>&#39; ; 
} 
?>

Output:

##Method 2: Through regular expression Formula to find matches

preg_match() function

preg_match() function is used to search for text using regular expressions An exact match of the pattern. Given a regular expression pattern, this function searches the text and finds an exact match, if one exists. This function returns true if it exists; false if it does not exist.

<?php 
header("content-type:text/html;charset=utf-8");  
// 在URL中查找特定的子字符串
  
// 给定URL
$url = &#39;http://www.php.cn/course/list/29.html&#39;; 
echo &#39;URL为： &#39;.$url.&#39; <br>&#39; ; 
// 搜索子字符串
$pattern = &#39;/\bphp\b/&#39;; 
  
if (preg_match($pattern, $url) == false) { 
    echo &#39;URL中不存在php <br>&#39;; 
} 
else { 
    echo &#39;URL中存在php <br>&#39;; 
} 
$pattern = &#39;/\bPHP\b/&#39;; 
  
if (preg_match($pattern, $url) == false) { 
    echo &#39;URL中不存在PHP&#39;; 
} 
else { 
    &#39;URL中不存在PHP&#39;; 
} 
?>

Output:

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