243

How can I turn a string below into an array?

pg_id=2&parent_id=2&document&video

This is the array I am looking for,

array(
    'pg_id' => 2,
    'parent_id' => 2,
    'document' => ,
    'video' =>
)
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1
  • 1
    The documentation for parse_str() does not explain it well. This is better (my emphasis): "Without the second argument to parse_str(), the query string parameters would populate the local symbol table. Given the security implications of this, using parse_str() without a second argument has now been deprecated." Commented Sep 19, 2021 at 19:51

12 Answers 12

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400

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.

$queryString = "pg_id=2&parent_id=2&document&video";
 
parse_str($queryString, $queryArray);

print_r($queryArray);
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7 Comments

I have a problem with this answer, because it does not work if you use the same key multiple times (yes because in php array keys are unique). So ?key=lorem&key=ipsum will result in array(["key"]=>"ipsum") The question is, is there a function to get s.th. like this array(["key"]=>array("lorem", "ipsum")) or do I have to create this function on my own?
Technically PHP would also treat ?key=lorem&key=ipsum as if you only provided key=ipsum if that were the query string on the URL. And I think it's considered invalid to reuse the key and expect consistent results or that all instances of the key are retained. The valid approach, at least for a query string sent to PHP, would be ?key[]=lorem&key[]=ipsum, so your homegrown approach might look for any occurrences of &{x}= where x occurs more than once and replace with x[] (and treating ? as same as &)
@Mabi - oh, and look, someone else agrees with you and created their own function already - php.net/manual/en/function.parse-str.php#76792
That was helpfull! I deciceded to do it like this ?key[]=lorem&key[]=ipsum some weeks ago. But thanks for sharing the link!
Something to watch out for are strings that include '+', like [email protected]. These will be parsed by parse_str to a space. key=myemail [email protected].
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76

Sometimes parse_str() alone is not accurate, it could display for example:

$url = "somepage?id=123&lang=gr&size=300";

parse_str() would return:

Array ( 
    [somepage?id] => 123 
    [lang] => gr 
    [size] => 300 
)

It would be better to combine parse_str() with parse_url() like so:

$url = "somepage?id=123&lang=gr&size=300";
parse_str( parse_url( $url, PHP_URL_QUERY), $array );
print_r( $array );
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2 Comments

I guess it is expecting $_SERVER['QUERY_STRING']
how to array to string url ex. : Array ( [somepage?id] => 123 [lang] => gr [size] => 300 ) output = somepage?id=123&lang=gr&size=300
39

Using parse_str().

$str = 'pg_id=2&parent_id=2&document&video';
parse_str($str, $arr);
print_r($arr);
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1 Comment

Perhaps add something about the deprecation of certain usages of parse_str? (But without "Edit:", "Update:", or similar - the answer should appear as if it was written today).
23

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' =>
)
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1 Comment

This was critical to remove the unwanted &
21

Use https://www.php.net/parse_str

Attention, its usage is:

parse_str($str, &$array);

not

$array = parse_str($str);

Please note that the above only applies to PHP version 5.3 and earlier. Call-time pass-by-reference has been removed in PHP 5.4.

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6 Comments

It's` parse_str($str,$arr);` and not parse_str($str,&$arr); terrible mistake
That is "&$arr" vs. "$arr" (& difference).
@user8241064: Isn't that just the formal parameters? (Yes, you have left the building, but perhaps somebody else can chime in?)
@pushrbx: It is not clear what should be used for later versions of PHP (or all versions of PHP). It is as if you are suggesting nothing applies for later versions of PHP (that is probably not the case or what you meant). Can you clarify? It is probably best in comments here first, before suggesting another edit.
@PeterMortensen I made my edit with the assumption that the reader knows what is meant by "call-time pass by reference" and that it has been removed. I meant that the correct syntax would be parse_str($str, $array); instead of parse_str($str, &$array); in future versions of PHP. Also according to SO guidelines, this bit of info should be there I think.
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20

There are several possible methods, but for you, there is already a built-in parse_str function:

$array = array();
parse_str($string, $array);
var_dump($array);
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1 Comment

Perhaps add something about the deprecation of certain usages of parse_str? (But without "Edit:", "Update:", or similar - the answer should appear as if it was written today).
6

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

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

3

You can try this code:

<?php
    $str = "pg_id=2&parent_id=2&document&video";
    $array = array();
    parse_str($str, $array);
    print_r($array);
?>

Output:

Array
(
    [pg_id] => 2
    [parent_id] => 2
    [document] =>
    [video] =>
)
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1 Comment

An explanation would be in order. E.g., what is the idea/gist? Please respond by editing (changing) your answer, not here in comments (without "Edit:", "Update:", or similar - the answer should appear as if it was written today).
2

But PHP already comes with a built in $_GET function. this will convert it to the array by itself.

try print_r($_GET) and you will get the same results.

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Comments

1

You can use the PHP string function parse_str() followed by foreach loop.

$str="pg_id=2&parent_id=2&document&video";
parse_str($str,$my_arr);
foreach($my_arr as $key=>$value){
  echo "$key => $value<br>";
}
print_r($my_arr);
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Comments

-3

This is the PHP code to split a query in MySQL and SQL Server:

function splitquery($strquery)
{
    $arrquery = explode('select', $strquery);

    $stry = ''; $strx = '';

    for($i=0; $i<count($arrquery); $i++)
    {
        if($i == 1)
        {
            echo 'select ' . trim($arrquery[$i]);
        }
        elseif($i > 1)
        {
            $strx = trim($arrquery[($i-1)]);

            if(trim(substr($strx,-1)) != '(')
            {
                $stry = $stry . '

                        select ' . trim($arrquery[$i]);
            }
            else
            {
                $stry = $stry.trim('select ' . trim($arrquery[$i]));
            }
            $strx = '';
        }
    }
    return $stry;
}

Example:

Query before

Select xx from xx select xx,(select xx) from xx where y='    cc'
select xx from xx left join (select xx) where (select top 1 xxx from xxx) oder by xxx desc";

Query after

select xx from xx

select xx,(select xx) from xx where y='    cc'

select xx from xx left join (select xx) where (select top 1 xxx from xxx) oder by xxx desc
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Comments

-5

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!

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1 Comment

You should never have the same query param name with different values. It does not make sense since only one will be accepted anyway.

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