Parse query string into an array

Question

How can I turn a string below into an array?

pg_id=2&parent_id=2&document&video 

This is the

Answer 1

For this specific question the chosen answer is correct but if there is a redundant parameter—like an extra "e"—in the URL the function will silently fail without an error or exception being thrown:

a=2&b=2&c=5&d=4&e=1&e=2&e=3 

So I prefer using my own parser like so:

//$_SERVER['QUERY_STRING'] = `a=2&b=2&c=5&d=4&e=100&e=200&e=300` 

$url_qry_str  = explode('&', $_SERVER['QUERY_STRING']);

//arrays that will hold the values from the url
$a_arr = $b_arr = $c_arr = $d_arr = $e_arr =  array();

foreach( $url_qry_str as $param )
    {
      $var =  explode('=', $param, 2);
      if($var[0]=="a")      $a_arr[]=$var[1];
      if($var[0]=="b")      $b_arr[]=$var[1];
      if($var[0]=="c")      $c_arr[]=$var[1];
      if($var[0]=="d")      $d_arr[]=$var[1];
      if($var[0]=="e")      $e_arr[]=$var[1];
    }

    var_dump($e_arr); 
    // will return :
    //array(3) { [0]=> string(1) "100" [1]=> string(1) "200" [2]=> string(1) "300" } 

Now you have all the occurrences of each parameter in its own array, you can always merge them into one array if you want to.

Hope that helps!

Answer 2

If you're having a problem converting a query string to an array because of encoded ampersands

&

then be sure to use html_entity_decode

Example:

// Input string //
$input = 'pg_id=2&parent_id=2&document&video';

// Parse //
parse_str(html_entity_decode($input), $out);

// Output of $out //
array(
  'pg_id' => 2,
  'parent_id' => 2,
  'document' => ,
  'video' =>
)

Answer 3

You want the parse_str function, and you need to set the second parameter to have the data put in an array instead of into individual variables.

$get_string = "pg_id=2&parent_id=2&document&video";

parse_str($get_string, $get_array);

print_r($get_array);

Answer 4

This is one-liner for parsing query from current URL into array:

parse_str($_SERVER['QUERY_STRING'], $query);