PHP advanced filter

Detect whether a number is within a range

The following example uses the filter_var() function to detect whether an INT type variable is within 1 to 200:

Example

<?php
$int = 122;
$min = 1;
$max = 200;
if (filter_var($int, FILTER_VALIDATE_INT, array("options" => array("min_range"=>$min, "max_range"=>$max))) === false) 
{    
echo("变量值不在合法范围内");
} else {    
echo("变量值在合法范围内");
}
?>

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Detect IPv6 address

The following example uses the filter_var() function to detect whether a $ip variable is an IPv6 address:

Example

<?php
$ip = "2001:0db8:85a3:08d3:1319:8a2e:0370:7334";
if (!filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6) === false) {
    echo("$ip 是一个 IPv6 地址");
} else {
    echo("$ip 不是一个 IPv6 地址");
}
?>

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Detect URL - must contain QUERY_STRING (query string)

The following example uses the filter_var() function to detect whether $url contains Query string:

Example

<?php
$url = "http://www.php.cn";
if (!filter_var($url, FILTER_VALIDATE_URL, FILTER_FLAG_QUERY_REQUIRED) === false) {
    echo("$url 是一个合法的 URL");
} else {
    echo("$url 不是一个合法的 URL");
}
?>

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Remove characters with ASCII values ​​greater than 127

The following example uses filter_var( ) function to remove characters with an ASCII value greater than 127 from a string. It can also remove HTML tags:

Example

<?php
$str = "<h1>Hello WorldÆØÅ!</h1>";
$newstr = filter_var($str, FILTER_SANITIZE_STRING, FILTER_FLAG_STRIP_HIGH);
echo $newstr;
?>

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PHP Filter Reference Manual

You can also view the specific application of filters by visiting the PHP Filter Reference Manual on this site.

The reference manual contains a brief description and usage examples of filter parameters!