Filters a variable with a specified filter

filter_var_array
Function Handling
Filter Functions
PHP Manual

# filter_var

(PHP 5 >= 5.2.0, PHP 7)

filter_var — Filters a variable with a specified filter

### Description

mixed filter_var ( mixed `$variable` [, int `$filter` = FILTER_DEFAULT [, mixed `$options` ]] )

### Parameters

`variable`

  Value to filter.

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

### See Also

- filter_var_array() - Gets multiple variables and optionally filters them
- filter_input() - Gets a specific external variable by name and optionally filters it
- filter_input_array() - Gets external variables and optionally filters them
- Types of filters
- information about the callback type

filter_var_array
Function Handling
Filter Functions
PHP Manual