PHP 5.6.0beta1 released

parse_str

(PHP 4, PHP 5)

parse_strParses the string into variables

Description

void parse_str ( string $str [, array &$arr ] )

Parses str as if it were the query string passed via a URL and sets variables in the current scope.

Note:

To get the current QUERY_STRING, you may use the variable $_SERVER['QUERY_STRING']. Also, you may want to read the section on variables from external sources.

Note:

The magic_quotes_gpc setting affects the output of this function, as parse_str() uses the same mechanism that PHP uses to populate the $_GET, $_POST, etc. variables.

Parameters

str

The input string.

arr

If the second parameter arr is present, variables are stored in this variable as array elements instead.

Return Values

No value is returned.

Changelog

Version Description
4.0.3 The arr parameter was added

Examples

Example #1 Using parse_str()

<?php
$str 
"first=value&arr[]=foo+bar&arr[]=baz";
parse_str($str);
echo 
$first;  // value
echo $arr[0]; // foo bar
echo $arr[1]; // baz

parse_str($str$output);
echo 
$output['first'];  // value
echo $output['arr'][0]; // foo bar
echo $output['arr'][1]; // baz

?>

See Also

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User Contributed Notes 34 notes

up
15
sean at getclicky dot com
5 years ago
This function automatically urldecodes values (not mentioned in the docs).
up
6
me at bubjavier dot com
4 years ago
be careful using parse_str() without the [array &$arr] parameter, as this may override values of global and existing variables.

<?php
$var1
= 1;
parse_str('var1=one&var2=two');
// $var1 is now 'one'
?>

Also may lead to variable value injection when used with user input data:

<?php
$_POST
['range'] = 'min=1&max=5&important_var=important_value_no_more';

$important_var = 'important_value';
parse_str($_POST['range']);
?>
up
2
Tore Bjølseth
8 years ago
As of PHP 5, you can do the exact opposite with http_build_query(). Just remember to use the optional array output parameter.

This is a very useful combination if you want to re-use a search string url, but also slightly modify it:

Example:
<?
$url1 = "action=search&interest[]=sports&interest[]=music&sort=id";
$str = parse_str($url1, $output);

// Modifying criteria:
$output['sort'] = "interest";

$url2 = http_build_query($output);

echo "<br>url1: ".$url1;
echo "<br>url2: ".$url2;
?>

Results in:
url1: action=search&interest[]=sports&interest[]=music&sort=id
url2: action=search&interest[0]=sports&interest[1]=music&sort=interest

(Array indexes are automatically created.)
up
4
Olivier Mengué
7 years ago
Vladimir: the function is OK in how it deals with &amp;.
&amp; must only be used when outputing URLs in HTML/XML data.
You should ask yourself why you have &amp; in your URL when you give it to parse_str.
up
2
chris at mcfadyen dot ca
6 years ago
I shouldn't've posted the original version, as it only worked with the most basic of query strings.

This function will parse an html-safe query-like url string for variables and php-like ordered and associative arrays.  It places them into the global scope as parse_str does and adds minimal slashes for database insertions without the triple-slash problems that magic quotes can produce (the reason I had to write it in the first place).  If you don't need the slashes, they're easy enough to remove.

<?php
function parse_query($str) {
   
   
// Separate all name-value pairs
   
$pairs = explode('&', $str);
   
    foreach(
$pairs as $pair) {
       
       
// Pull out the names and the values
       
list($name, $value) = explode('=', $pair, 2);
       
       
// Decode the variable name and look for arrays
       
list($name, $index) = split('[][]', urldecode($name));
       
       
// Arrays
       
if(isset($index)) {
           
           
// Declare or add to the global array defined by $name
           
global $$name;
            if(!isset($
$name)) $$name = array();
           
           
// Associative array
           
if($index != "") {
                ${
$name}[$index] = addslashes(urldecode($value));
               
           
// Ordered array
           
} else {
               
array_push($$name, addslashes(urldecode($value)));
            }
       
       
// Variables
       
} else {
           
           
// Declare or overwrite the global variable defined by $name
           
global $$name;
            $
$name = addslashes(urldecode($value));
        }
    }
}
?>
up
1
avi at amarcus dot com
8 years ago
If you are trying to preserve a complex array, the function serialize might be better than http_build_query or other methods of making a query string.
up
1
anatilmizun at gmail dot com
9 years ago
I wrote a pair of functions using parse_str() that will write values in an array to a textfile and vice versa, read those values from the textfile back into the array. Quite useful if you need to store lots of data but don't have access to SQL.

Save the array by calling cfg_save($filename,$array) and load it back using $array=cfg_load($filename)

<?php
$newline
="€";

function
cfg_load($cfgfile){
    global
$newline;
   
$setting="";
    if(
file_exists($cfgfile)){
       
$setting=fopen($cfgfile, "r");
       
$ookk="";
        while(
$ook=fgets($setting)){
           
#strip comment
           
$commt=strpos($ook,"##");
            if(
$commt!==false) $ook=substr($ook,0,$commt);
           
#append
           
if($ook!="") $ookk=$ookk."&".    str_replace($newline,"\n",str_replace("&","%26",trim($ook)));
        }   
       
fclose($setting);   
       
parse_str($ookk, $setting);
    }
    return
$setting;
}

function
cfg_save($cfgfile,$setting){
    global
$intArray;
   
$intArray="";
    for(
$i=0;$i<2000;$i++)
       
$intArray[]=$i;
    if(
is_array($setting)){
       
$allkeys=array_keys($setting);
        foreach(
$allkeys as $aKey)
           
cfg_recurse($setting[$aKey], $aKey, $outArray);
    }
   
$cfgf=fopen($cfgfile,"w");
    foreach(
$outArray as $aLine)
       
fputs($cfgf,stripslashes($aLine)."\r\n");
   
fclose($cfgf);
}

function
cfg_recurse($stuffIn, $keysofar, &$toAppend){
    global
$intArray, $newline;
    if(
is_array($stuffIn)){
       
$allkeys=array_keys($stuffIn);
        if(
array_slice($intArray,0,sizeof($allkeys))==$allkeys)
           
$nokey=true;
        else
           
$nokey=false;
        foreach(
$allkeys as $aKey){
            if(!
$nokey) $toKey=$aKey;   
           
cfg_recurse($stuffIn[$aKey], $keysofar."[".$toKey."]", $toAppend);
        }
    }else
       
$toAppend[]=$keysofar."=".str_replace("\n",$newline,$stuffIn);
}
?>

Note that these functions support nested arrays of unlimited levels ;)
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2
kermodebear at kermodebear dot org
6 years ago
An old post from several years ago mentions that variable names cannot have a dot. They also cannot have a space. Spaces are automatically replaced with an underscore.

The following:
parse_str("My Value=Something", $result);

Will result in:
$result['My_Value'] = 'Something'

Although I understand why it is done, I still feel that this is unintuitive behavior.
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2
PEPE_RIVAS at repixel dot net
7 years ago
CONVERT ANY FORMATTED STRING INTO VARIABLES

I developed a online payment solution for credit cards using a merchant, and this merchant returns me an answer of the state of the transaction like this:

estado=1,txnid=5555444-8454445-4455554,monto=100.00

to have all that data into variables could be fine for me! so i use str_replace(), the problem is this function recognizes each group of variables with the & character... and i have  comma separated values... so i replace comma with &

<?php
$string
= "estado=1,txnid=5555444-8454445-4455554,monto=100.00";
$string = str_replace(",","&",$string);
parse_str($string);
echo
$monto; // outputs 100.00
?>
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2
jrgns at jadeit dot co dot za
1 year ago
The array to be populated does not need to be defined before calling the function:

<?php
error_reporting
(E_ALL | E_STRICT);
parse_str('var=value', $array);
?>

This will not produce a notice.
up
1
helpmepro1 at gmail dot com
5 years ago
<?
//by shimon doodkin

 $url_form=url_to_form($url);
 echo '<form action="'.$url_form['action'].'" method="get">';
 echo $url_form['hidden'];
 echo '<input name="otherfiled" type="text">';
 echo '<input type="submit">';
 echo '</form>';

 function url_to_form($url)
 {
  $url=split('\?',$url,2);
  $action=$url[0];
  $hidden="";
  if(isset($url[1]))
  {
   $pairs=split('&',$url[1]);
   foreach($pairs as $pair)
   {
    $pair=split('=',$pair,2);
    $name=$pair[0];
    if(isset($pair[1]))
     $value=$pair[1];
    else
     $value='';
    $name=$name;
    $value=htmlspecialchars($value);
    if($name!='')
     $hidden.='<hidden name="'.$name.'" value="'.$value.'">';
   }
  }
  return array('action'=>$action,'hidden'=>$hidden);
 }

?>
up
1
Evan K
6 years ago
It bears mentioning that the parse_str builtin does NOT process a query string in the CGI standard way, when it comes to duplicate fields.  If multiple fields of the same name exist in a query string, every other web processing language would read them into an array, but PHP silently overwrites them:

<?php
# silently fails to handle multiple values
parse_str('foo=1&foo=2&foo=3');

# the above produces:
$foo = array('foo' => '3');
?>

Instead, PHP uses a non-standards compliant practice of including brackets in fieldnames to achieve the same effect.

<?php
# bizarre php-specific behavior
parse_str('foo[]=1&foo[]=2&foo[]=3');

# the above produces:
$foo = array('foo' => array('1', '2', '3') );
?>

This can be confusing for anyone who's used to the CGI standard, so keep it in mind.  As an alternative, I use a "proper" querystring parser function:

<?php
function proper_parse_str($str) {
 
# result array
 
$arr = array();

 
# split on outer delimiter
 
$pairs = explode('&', $str);

 
# loop through each pair
 
foreach ($pairs as $i) {
   
# split into name and value
   
list($name,$value) = explode('=', $i, 2);
   
   
# if name already exists
   
if( isset($arr[$name]) ) {
     
# stick multiple values into an array
     
if( is_array($arr[$name]) ) {
       
$arr[$name][] = $value;
      }
      else {
       
$arr[$name] = array($arr[$name], $value);
      }
    }
   
# otherwise, simply stick it in a scalar
   
else {
     
$arr[$name] = $value;
    }
  }

 
# return result array
 
return $arr;
}

$query = proper_parse_str($_SERVER['QUERY_STRING']);
?>
up
0
markc
9 months ago
Beware using parse_str in a function that has vars passed by reference. It seems that parse_str actually creates new vars even if vars of the same name exist. If you pass by ref vars of the same name as those in a query string being parsed new LOCAL vers will be created and you won't get any values passed back to the caller (relates to what Maikel mentioned below)

An unrealistic example (vaguely related to what I was doing when I found this out)...

function get_title($query,&$title)
{
  parse_str($query);
  $title=str_replace("_"," ",$title);
}

$title="foo";
$query = "context=something&title=Title_of_Something";
get_title($query,$title);

echo $title .... "foo"
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0
shagshag
1 year ago
That's not says in the description but max_input_vars directive affects this function. If there are more input variables on the string than specified by this directive, an E_WARNING is issued, and further input variables are truncated from the request.
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0
Benjamin Garcia
1 year ago
function like parse_str, but doesn't convert spaces and dots to underscores in $_GET AND $_POST

/**
 * GET and POST input containing dots, etc.
 */
function getRealREQUEST() {
    $vars = array();

    $input    = $_SERVER['REDIRECT_QUERY_STRING'];
    if(!empty($input)){
        $pairs    = explode("&", $input);
        foreach ($pairs     as $pair) {
            $nv                = explode("=", $pair);
           
            $name            = urldecode($nv[0]);
            $nameSanitize    = preg_replace('/([^\[]*)\[.*$/','$1',$name);
           
            $nameMatched    = str_replace('.','_',$nameSanitize);
            $nameMatched    = str_replace(' ','_',$nameMatched);
           
            $vars[$nameSanitize]    = $_REQUEST[$nameMatched];
        }
    }
   
    $input    = file_get_contents("php://input");
    if(!empty($input)){
        $pairs    = explode("&", $input);
        foreach ($pairs as $pair) {
            $nv                = explode("=", $pair);
           
            $name            = urldecode($nv[0]);
            $nameSanitize    = preg_replace('/([^\[]*)\[.*$/','$1',$name);
           
            $nameMatched    = str_replace('.','_',$nameSanitize);
            $nameMatched    = str_replace(' ','_',$nameMatched);
           
            $vars[$nameSanitize]    = $_REQUEST[$nameMatched];
        }
    }
   
    return $vars;
}
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0
sam dot fullman at verizon dot net
3 years ago
If you're using .htaccess to spoof pages in any type of application, then $QUERY_STRING or $_SERVER['QUERY_STRING'] is going to be blank.  Instead, $_SERVER['REDIRECT_QUERY_STRING'] will hold the actual query string passed by user.  Use this function to parse this variable.
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0
tobsn at php dot net
5 years ago
just a heads up with the example above:
?var[]=123 - the [] has to be urlencoded.
var names and var values - both have to be urlencoded!
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0
chris at mcfadyen dot ca
6 years ago
If you wish a version of parse_str sans magic quotes, the following will do the trick:

<?php
function parse_query($str) {
   
$pairs = explode('&', $str);

    foreach(
$pairs as $pair) {
        list(
$name, $value) = explode('=', $pair, 2);
        global $
$name;
        $
$name = $value;
    }
}
?>
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0
Vladimir Kornea
6 years ago
parse_str() is confused by ampersands (&) being encoded as HTML entities (&amp;). This is relevant if you're extracting your query string from an HTML page (scraping). The solution is to run the string through html_entity_decode() before running it through parse_str().

(Editors: my original comment was a caution whose solution is obvious, but it has resulted in three replies ("so what?" "as intended" and "this is how to fix it"). Please remove the previous four posts dealing with this (69529, 70234, 72745, 74818) and leave just the above summary. This issue is too trivial to warrant the number of comments it has received.)
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0
Vladimir Kornea
6 years ago
parse_str() contained a bug (#39763) in PHP 5.2.0 that caused it to apply magic quotes twice. This bug was marked as fixed in the release notes of PHP 5.2.1, but there were apparently some issues with getting the fix through CVS on time, as our install of PHP 5.2.1 was still affected by it.
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0
mike dot coley at inbox dot com
6 years ago
Here is a little function that does the opposite of the parse_str function. It will take an array and build a query string from it.

<?php

/* Converts an array of parameters into a query string to be appended to a URL.
 *
 * @return  string              : Query string to append to a URL.
 * @param   array    $array     : Array of parameters to append to the query string.
 * @param   string   $parent    : This should be left blank (it is used internally by the function).
 */
function append_params($array, $parent='')
{
   
$params = array();
    foreach (
$array as $k => $v)
    {
        if (
is_array($v))
           
$params[] = append_params($v, (empty($parent) ? urlencode($k) : $parent . '[' . urlencode($k) . ']'));
        else
           
$params[] = (!empty($parent) ? $parent . '[' . urlencode($k) . ']' : urlencode($k)) . '=' . urlencode($v);
    }

   
$sessid = session_id();
    if (!empty(
$parent) || empty($sessid))
        return
implode('&', $params);

   
// Append the session ID to the query string if we have to.
   
$sessname = session_name();
    if (
ini_get('session.use_cookies'))
    {
        if (!
ini_get('session.use_only_cookies') && (!isset($_COOKIE[$sessname]) || ($_COOKIE[$sessname] != $sessid)))
           
$params[] = $sessname . '=' . urlencode($sessid);
    }
    elseif (!
ini_get('session.use_only_cookies'))
       
$params[] = $sessname . '=' . urlencode($sessid);

    return
implode('&', $params);
}

?>

Note that the function will also append the session ID to the query string if it needs to be.
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0
php at voodoolabs dot net
7 years ago
This is probably a better solution than below. The first line makes sure the file doesn't exist then the second line directs all requests to a script. No need to output a 200 header with this method either.

RewriteEngine On

RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ index.php      [L]
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0
lenix.de
7 years ago
if you would like to get a nice url scheme with php/apache and and want to handle all requests in a central php script there's a simple solution/hack:

create a .htaccess in your "basedir" where you've got your main script (in this example index.php) containing some lines like:

"ErrorDocument 404 /index.php"

inside index.php you can now do

<?php
    $virtual_path
= substr(
       
$_SERVER['REQUEST_URI'],
       
strlen( dirname( $_SERVER['PHP_SELF'] ) ) + 1
   
);
    if( (
$pos = strpos( $virtual_path, '?' )) !== false ) {
       
parse_str( substr( $virtual_path, $pos + 1 ), $_GET );
       
$_REQUEST = array_merge( $_REQUEST, $_GET );
       
$virtual_path = substr( $virtual_path, 0, $pos );
    }

   
// some code checking for a valid location, etc...
   
header( 'HTTP/1.1 200 OK' );
   
header( 'Content-Type: text/plain' );

    echo
$virtual_path."\n\n";
   
print_r( $_REQUEST );
?>

// guido 'lenix' boehm
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0
jgbreezer at gmail dot com
7 years ago
Vladimir Kornea wrote on 8 Sep 2006:
"This function is confused by ampersands (&) being encoded as HTML entities (&amp;)"

Well, it would be - it's not supposed to be passed html entities, that's a different encoding scheme. This function does correctly decode url encoded params for you though (with the rawurlencode rather than urlencode, ie '+' is translated to a space).
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0
Vladimir Kornea
7 years ago
This function is confused by ampersands (&) being encoded as HTML entities (&amp;).

$str = "first=value&amp;arr[]=foo+bar&amp;arr[]=baz";
parse_str($str, $output);
print_r($output);

Array
(
    [first] => value
    [amp;arr] => Array
        (
            [0] => foo bar
            [1] => baz
        )
)
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0
motin at demomusic dot nu
8 years ago
When you have scripts run through the command-line (like locally via cron), you might want to be able to use _GET and _POST vars. Put this in top of your scheduled task files:

<?
    parse_str ($_SERVER['argv'][1], $GLOBALS['_GET']);
    parse_str ($_SERVER['argv'][2], $GLOBALS['_POST']);
?>

And call your script by:

/usr/local/bin/php /path/to/script.php "id=45&action=delete" "formsubmitted=true"

Cheers!
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0
kerosuppi
8 years ago
This does not work as expected.

<?php
class someclass
{
    var
$query_string;
    function
someclass($a_query_string)
    {
       
$this->query_string = $a_query_string;
       
parse_str($this->query_string);
    }
    function
output()
    {
        echo
$this->action;
    }
}

$a_class = new someclass("action=go");
$a_class->output();
?>

Use this instead.

<?php
class someclass
{
    var
$arr;
    function
someclass($a_query_string)
    {
       
parse_str($a_query_string, $this->arr);
    }
    function
output()
    {
        echo
$this->arr['action'];
    }
}

$a_class = new someclass("action=go");
$a_class->output();
?>
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0
mortoray at ecircle-ag dot com
8 years ago
In Kent's solution you may wish to switch "urldecode" into "rawurldecode" if you'd like to get rid of the [annoying] plus '+' converted to space ' ' translation.
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0
kent at nospam dot ioflux dot com
8 years ago
You may want to parse the query string into an array.

<?php
/**
 * Similar to parse_str. Returns false if the query string or URL is empty. Because we're not parsing to
 * variables but to array key entries, this function will handle ?[]=1&[]=2 "correctly."
 *
 * @return array Similar to the $_GET formatting that PHP does automagically.
 * @param string $url A query string or URL
 * @param boolean $qmark Find and strip out everything before the question mark in the string
*/
function parse_query_string($url, $qmark=true)
{
    if (
$qmark) {
       
$pos = strpos($url, "?");
        if (
$pos !== false) {
           
$url = substr($url, $pos + 1);
        }
    }
    if (empty(
$url))
        return
false;
   
$tokens = explode("&", $url);
   
$urlVars = array();
    foreach (
$tokens as $token) {
       
$value = string_pair($token, "=", "");
        if (
preg_match('/^([^\[]*)(\[.*\])$/', $token, $matches)) {
           
parse_query_string_array($urlVars, $matches[1], $matches[2], $value);
        } else {
           
$urlVars[urldecode($token)] = urldecode($value);
        }
    }
    return
$urlVars;
}

/**
 * Utility function for parse_query_string. Given a result array, a starting key, and a set of keys formatted like "[a][b][c]"
 * and the final value, updates the result array with the correct PHP array keys.
 *
 * @return void
 * @param array $result A result array to populate from the query string
 * @param string $k The starting key to populate in $result
 * @param string $arrayKeys The key list to parse in the form "[][a][what%20ever]"
 * @param string $value The value to place at the destination array key
*/
function parse_query_string_array(&$result, $k, $arrayKeys, $value)
{
    if (!
preg_match_all('/\[([^\]]*)\]/', $arrayKeys, $matches))
        return
$value;
    if (!isset(
$result[$k])) {
       
$result[urldecode($k)] = array();
    }
   
$temp =& $result[$k];
   
$last = urldecode(array_pop($matches[1]));
    foreach (
$matches[1] as $k) {
       
$k = urldecode($k);
        if (
$k === "") {
           
$temp[] = array();
           
$temp =& $temp[count($temp)-1];
        } else if (!isset(
$temp[$k])) {
           
$temp[$k] = array();
           
$temp =& $temp[$k];
        }
    }
    if (
$last === "") {
       
$temp[] = $value;
    } else {
       
$temp[urldecode($last)] = $value;
    }
}

/**
* Breaks a string into a pair for a common parsing function.
*
* The string passed in is truncated to the left half of the string pair, if any, and the right half, if anything, is returned.
*
* An example of using this would be:
* <code>
* $path = "Account.Balance";
* $field = string_pair($path);
*
* $path is "Account"
* $field is "Balance"
*
* $path = "Account";
* $field = string_pair($path);
*
* $path is "Account"
* $field is false
* </code>
*
* @return string The "right" portion of the string is returned if the delimiter is found.
* @param string $a A string to break into a pair. The "left" portion of the string is returned here if the delimiter is found.
* @param string $delim The characters used to delimit a string pair
* @param mixed $default The value to return if the delimiter is not found in the string
* @desc
*/
function string_pair(&$a, $delim='.', $default=false)
{
   
$n = strpos($a, $delim);
    if (
$n === false)
        return
$default;
   
$result = substr($a, $n+strlen($delim));
   
$a = substr($a, 0, $n);
    return
$result;
}

?>
up
0
Matt Curtis
9 years ago
If the querystring contains duplicate keys in the key-value pairs, parse_str will only return the last instance of the value.  For example, in the following:

<?php
$mystr
= "test1=blah&test2=bleh&test1=burp";
parse_str($mystr, $myarray);
echo
$myarray['test1'];
?>
The value output will be 'burp'. 

I wrote a function that takes a querystring and returns the the key-value pairs as a two-dimensional array so each duplicate key is available:

<?php
$str
= "test1=blah&test2=bleh&test1=burp";
$valsarray = parse_str_ext($str);
echo
$valsarray['test1'][0];
echo
$valsarray['test1'][1];
echo
$valsarray['test2'][0];

function
parse_str_ext($toparse) {
   
$returnarray = array();
   
$keyvaluepairs = split("&", $toparse);
    foreach(
$keyvaluepairs as $pairval) {
       
$splitpair = split("=", $pairval);
        if(!
array_key_exists($splitpair[0], $returnarray)) $returnarray[$splitpair[0]] = array();

       
$returnarray[$splitpair[0]][] = $splitpair[1];
    }
    return
$returnarray;   
}
?>

Output will be:
blah
burp
bleh
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0
Anonymous
9 years ago
Note that variables cannot contain a DOT (.) in PHP. So, DOT will be replaced by underscore.
e.g. variables like "variable.something" will be converted into "variable_something".
up
0
Anonymous
10 years ago
The documentation does not appear to mention that parse_str also urldecodes each item in the resulting array.

There also appears to be a bug in earlier versions of PHP that causes these urldecoded strings to also be escaped.  (Certainly I was having problems with %22 being turned into /" on my server, but not on my development box, despite forcing magic quotes off).
up
-1
Michal Zalewski
6 years ago
Vladimir Kornea:
Try use html_entity_decode()

$str = 'first=value&amp;arr[]=foo+bar&amp;arr[]=baz';
parse_str(html_entity_decode($str), $output);
print_r($output);

Array
(
    [first] => value
    [arr] => Array
        (
            [0] => foo bar
            [1] => baz
        )

)
up
-1
Will Voelcker
3 years ago
If you need a function that does something similar to parse_str, but doesn't convert spaces and dots to underscores, try something like the following:

<?php
function parseQueryString($str) {
   
$op = array();
   
$pairs = explode("&", $str);
    foreach (
$pairs as $pair) {
        list(
$k, $v) = array_map("urldecode", explode("=", $pair));
       
$op[$k] = $v;
    }
    return
$op;
}
?>

It may need adapting to handle various edge cases.
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