List of Php filter types

PHP provides a set of built-in filters that can be used to validate and sanitize data.

Here is a list of the most common PHP filter types:

Filter types list

These filters can be used with the filter_var() function, which takes two parameters: the value to be filtered and the filter type.

Example

<?php
$website = "https://www.example.com";
if (filter_var($website, FILTER_VALIDATE_URL)) {
    echo "URL is valid";
} else {
    echo "URL is not valid";
}
?>

Examples by Filter types

All Php filters examples.

FILTER_VALIDATE_INT

<?php
$age = "25";
if (filter_var($age, FILTER_VALIDATE_INT)) {
    echo "Age is valid";
} else {
    echo "Age is not valid";
}
?>

FILTER_VALIDATE_FLOAT

<?php
$price = "19.99";
if (filter_var($price, FILTER_VALIDATE_FLOAT)) {
    echo "Price is valid";
} else {
    echo "Price is not valid";
}
?>

FILTER_VALIDATE_BOOLEAN

<?php
$bool = "true";
if (filter_var($bool, FILTER_VALIDATE_BOOLEAN)) {
    echo "Boolean is valid";
} else {
    echo "Boolean is not valid";
}
?>

FILTER_VALIDATE_EMAIL

<?php
$email = "john.doe@example.com";
if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
    echo "Email is valid";
} else {
    echo "Email is not valid";
}
?>

FILTER_VALIDATE_URL

<?php
$website = "https://www.example.com";
if (filter_var($website, FILTER_VALIDATE_URL)) {
    echo "URL is valid";
} else {
    echo "URL is not valid";
}
?>

FILTER_VALIDATE_IP

<?php
$ip = "127.0.0.1";
if (filter_var($ip, FILTER_VALIDATE_IP)){
    echo "IP is valid";
} else {
    echo "IP is not valid";
}
?>

FILTER_VALIDATE_REGEXP

<?php
$string = "abc123";
if (filter_var($string, FILTER_VALIDATE_REGEXP, array("options" => array("regexp" => "/^[a-z]+\d+$/")))) {
    echo "String is valid";
} else {
    echo "String is not valid";
}
?>

FILTER_SANITIZE_STRING

<?php
$string = "<p>Hello, <b>world</b>!</p>";
$string = filter_var($string, FILTER_SANITIZE_STRING);
echo $string; // Outputs: "Hello, world!"
?>

FILTER_SANITIZE_ENCODED

<?php
$string = "Hello, world!";
$string = filter_var($string, FILTER_SANITIZE_ENCODED);
echo $string; // Outputs: "Hello%2C+world%21"
?>

FILTER_SANITIZE_SPECIAL_CHARS

<?php
$string = "Hello, <b>world</b>!";
$string = filter_var($string, FILTER_SANITIZE_SPECIAL_CHARS);
echo $string; // Outputs: "Hello, &lt;b&gt;world&lt;/b&gt;!"
?>

FILTER_SANITIZE_EMAIL

<?php
$email = "john.doe@example.com";
$email = filter_var($email, FILTER_SANITIZE_EMAIL);
echo $email; // Outputs: "john.doe@example.com"
?>

FILTER_SANITIZE_URL

<?php
$url = "https://www.example.com?param=value";
$url = filter_var($url, FILTER_SANITIZE_URL);
echo $url; // Outputs: "https://www.example.com?param=value"
?>

FILTER_SANITIZE_NUMBER_INT

<?php
$number = "25";
$number = filter_var($number, FILTER_SANITIZE_NUMBER_INT);
echo $number; // Outputs: 25
?>

FILTER_SANITIZE_NUMBER_FLOAT

<?php
$number = "19.99";
$number = filter_var($number, FILTER_SANITIZE_NUMBER_FLOAT);
echo $number; // Outputs: 19.99
?>

FILTER_SANITIZE_MAGIC_QUOTES

<?php
$string = "Hello, 'world'!";
$string = filter_var($string, FILTER_SANITIZE_MAGIC_QUOTES);
echo $string; // Outputs: "Hello, \'world\'!"
?>

These filters can be used to validate and sanitize user input, like form data, to ensure that it is safe to use in your application. Keep in mind that using multiple filters and validation methods is a good practice for securing your application.