filter_var(3) [php man page]

FILTER_VAR(3)								 1							     FILTER_VAR(3)

filter_var - Filters a variable with a specified filter

SYNOPSIS

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

DESCRIPTION

PARAMETERS

	      o $variable
		- Value to filter.

	      o $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.

	      o $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 fil-
		tered, 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(3) 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(3), filter_input(3), filter_input_array(3), "Types of filters", information about the callback type.

PHP Documentation Group 													     FILTER_VAR(3)

EMPTY(3)								 1								  EMPTY(3)

empty - Determine whether a variable is empty

SYNOPSIS

       bool empty (mixed  $var)

DESCRIPTION

	Determine  whether a variable is considered to be empty. A variable is considered empty if it does not exist or if its value equals FALSE.
       empty(3) does not generate a warning if the variable does not exist.

PARAMETERS

	      o $var
		- Variable to be checked

	      Note

		      Prior to PHP 5.5, empty(3) only supports variables; anything else will result in a parse error. In other words, the  follow-
		     ing will not work: empty(trim($name)). Instead, use trim($name) == false.

	       No  warning  is generated if the variable does not exist. That means empty(3) is essentially the concise equivalent to !isset($var)
	      || $var == false.

RETURN VALUES

	Returns FALSE if $var exists and has a non-empty, non-zero value. Otherwise returns TRUE.

	The following things are considered to be empty:

	      o "" (an empty string)

	      o 0 (0 as an integer)

	      o 0.0 (0 as a float)

	      o "0" (0 as a string)

	      o NULL

	      o FALSE

	      o array() (an empty array)

	      o $var; (a variable declared, but without a value)

CHANGELOG

       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 5.5.0	|						    |
       |	|						    |
       |	| empty(3) now supports  expressions,  rather  than |
       |	| only variables.				    |
       |	|						    |
       | 5.4.0	|						    |
       |	|						    |
       |	|  Checking  non-numeric offsets of strings returns |
       |	| TRUE. 					    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES

       Example #1

	       A simple empty(3) / isset(3) comparison.

	      <?php
	      $var = 0;

	      // Evaluates to true because $var is empty
	      if (empty($var)) {
		  echo '$var is either 0, empty, or not set at all';
	      }

	      // Evaluates as true because $var is set
	      if (isset($var)) {
		  echo '$var is set even though it is empty';
	      }
	      ?>

       Example #2

	      empty(3) on String Offsets

	       PHP 5.4 changes how empty(3) behaves when passed string offsets.

	      <?php
	      $expected_array_got_string = 'somestring';
	      var_dump(empty($expected_array_got_string['some_key']));
	      var_dump(empty($expected_array_got_string[0]));
	      var_dump(empty($expected_array_got_string['0']));
	      var_dump(empty($expected_array_got_string[0.5]));
	      var_dump(empty($expected_array_got_string['0.5']));
	      var_dump(empty($expected_array_got_string['0 Mostel']));
	      ?>

	      Output of the above example in PHP 5.3:

	      bool(false)
	      bool(false)
	      bool(false)
	      bool(false)
	      bool(false)
	      bool(false)

	      Output of the above example in PHP 5.4:

	      bool(true)
	      bool(false)
	      bool(false)
	      bool(false)
	      bool(true)
	      bool(true)

NOTES

       Note

	      Because this is a language construct and not a function, it cannot be called using variable functions.

       Note

	       When using empty(3) on inaccessible object properties, the __isset() overloading method will be called, if declared.

SEE ALSO

       isset(3), __isset(), unset(3), array_key_exists(3), count(3), strlen(3), The type comparison tables.

PHP Documentation Group 														  EMPTY(3)