Filter Functions
PHP Manual

filter_var

Filters a variable with a specified filter

Description

mixed filter_var(mixed $value, int $filter = FILTER_DEFAULT, arrayint $options = 0)

Parameters

value

Value to filter. Note that scalar values are converted to string internally before they are filtered.

filter

The ID of the filter to apply. The Types of filters manual page lists the available filters.

If omitted, FILTER_DEFAULT will be used, which is equivalent to FILTER_UNSAFE_RAW. This will result in no filtering taking place by default.

options

Associative array of options or bitwise disjunction of flags. If filter accepts options, flags can be provided in "flags" field of array. For the "callback" filter, callable type should be passed. The callback must accept one argument, the value to be filtered, and return the value after filtering/sanitizing it. 

<?php
// for filters that accept options, use this format
$options = array(
    'options' => array(
        'default' => 3, // value to return if the filter fails
        // other options here
        'min_range' => 0
    ),
    'flags' => FILTER_FLAG_ALLOW_OCTAL,
);
$var = filter_var('0755', FILTER_VALIDATE_INT, $options);

// for filters that only accept flags, you can pass them directly
$var = filter_var('oops', FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE);

// for filters that only accept flags, you can also pass as an array
$var = filter_var('oops', FILTER_VALIDATE_BOOLEAN,
                  array('flags' => FILTER_NULL_ON_FAILURE));

// callback validate filter
function foo($value)
{
    // Expected format: Surname, GivenNames
    if (strpos($value, ", ") === false) return false;
    list($surname, $givennames) = explode(", ", $value, 2);
    $empty = (empty($surname) || empty($givennames));
    $notstrings = (!is_string($surname) || !is_string($givennames));
    if ($empty || $notstrings) {
        return false;
    } else {
        return $value;
    }
}
$var = filter_var('Doe, Jane Sue', FILTER_CALLBACK, array('options' => 'foo'));
?>

Return Values

Returns the filtered data, or false if the filter fails.

Examples

Example #1 A filter_var example

<?php
var_dump(filter_var('bob@example.com', FILTER_VALIDATE_EMAIL));
var_dump(filter_var('http://example.com', FILTER_VALIDATE_URL, FILTER_FLAG_PATH_REQUIRED));
?>

The above example will output:

string(15) "bob@example.com"
bool(false)

Example #2 Filter an array example

<?php
$emails = [
    "bob@example.com",
    "test@example.local",
    "invalidemail"
];

var_dump(filter_var($emails, FILTER_VALIDATE_EMAIL, FILTER_REQUIRE_ARRAY));
?>

The above example will output:

array(3) {
  [0]=>
  string(15) "bob@example.com"
  [1]=>
  string(18) "test@example.local"
  [2]=>
  bool(false)
}

See Also