convert string to array

Question

I have this string: test1__test2__test3__test4__test5__test6=value

There could be any number of test-keys.

I want to write a function that can turn the string above into an array

$data[test1][test2][test3][test4][test5][test6] = "value";

Is this possible?

@Salman: "There could be any number of test-keys." -- I guess 6 is an arbitrary example. — Ferdinand Beyer
– Ferdinand Beyer, Commented Jun 20, 2011 at 14:47

Emil Vikström · Accepted Answer · 2011-06-20 13:59:25Z

3

function special_explode($string) {
  $keyval = explode('=', $string);
  $keys = explode('__', $keyval[0]);
  $result = array();

  //$last is a reference to the latest inserted element                         
  $last =& $result;
  foreach($keys as $k) {
    $last[$k] = array();
    //Move $last                                                                
    $last =& $last[$k];
  }

  //Set value                                                                   
  $last = $keyval[1];
  return $result;
}

//Test code:
$string = 'test1__test2__test3__test4__test5__test6=value';
print_r(special_explode($string));

answered Jun 20, 2011 at 13:59

Emil Vikström

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Felix Kling · Accepted Answer · 2011-06-21 08:30:02Z

3

Yes it is possible:

list($keys, $value) = explode('=', $str);
$keys = explode('__', $keys);

$t = &$data;
$last = array_pop($keys);

foreach($keys as $key) {
    if(!isset($t[$key]) || !is_array($t[$key])) {
        // will override non array values if present
        $t[$key] = array();
    }
    $t = &$t[$key];
}

$t[$last] = $value;

DEMO

Reference: list, explode, =&, is_array, array_pop

edited Jun 21, 2011 at 8:30

answered Jun 20, 2011 at 13:58

Felix Kling

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5 Comments

Felix Kling Over a year ago

@Ferdinand: Thanks! That happens when you code too fast :D ;)

Ferdinand Beyer Over a year ago

Furthermore, is_array($data[$key]) will issue warnings (or even errors?) if $key is not in $data. Did you mean isset()? ;)

Felix Kling Over a year ago

@Ferdinand: You are right, it gives a notice. But no, I wanted to use is_array. Just have to add isset. Thanks again! :)

Rasmus Styrk Over a year ago

Thank you for the references.

Salman Arshad Over a year ago

if you look at the output of the demo more closely you'll notice test6 appears twice.

Ferdinand Beyer · Accepted Answer · 2011-06-20 14:31:00Z

2

$data = array();

// Supposing you have multiple strings to analyse...
foreach ($strings as $string) {
    // Split at '=' to separate key and value parts.
    list($key, $value) = explode("=", $string);

    // Current storage destination is the root data array.
    $current =& $data;

    // Split by '__' and remove the last part
    $parts = explode("__", $key);
    $last_part = array_pop($parts);

    // Create nested arrays for each remaining part.
    foreach ($parts as $part)
    {
        if (!array_key_exists($part, $current) || !is_array($current[$part])) {
            $current[$part] = array();
        }
        $current =& $current[$part];
    }

    // $current is now the deepest array ($data['test1']['test2'][...]['test5']).
    // Assign the value to his array, using the last part ('test6') as key.
    $current[$last_part] = $value;
}

edited Jun 20, 2011 at 14:31

answered Jun 20, 2011 at 13:58

Ferdinand Beyer

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1 Comment

Rasmus Styrk Over a year ago

thanks for that. I needed to analyze a lot of strings and then compile one big array.

ajreal · Accepted Answer · 2011-06-20 14:00:18Z

1

$str = ...;
eval( str_replace('__', '][', 
preg_replace('/^(.*)=(.*)$/', '\$data[$1]=\'$2\';', $str)) );

easier way, assuming the $str is trustable data

answered Jun 20, 2011 at 14:00

ajreal

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2 Comments

Ferdinand Beyer Over a year ago

You should at least add quotes to the keys. Otherwise you will get warnings that you use undefined constants, and, if one of the keys happens to be a constant name, you will get into trouble. Maybe you should also emphasize the trustable aspect...

Slava Over a year ago

Agree with Ferinand. But otherwise nice solution. It's the first piece of code with eval I see, which I would've accepted in my own project 8) .

SteeveDroz · Accepted Answer · 2011-06-20 14:03:14Z

0

I suppose it is...

$string = "test1__test2__test3__test4__test5__test6=value";
$values = explode('=',$string);
$indexes = explode('__',$values[0]);
$data[$indexes[0]][$indexes[1]][$indexes[2]][$indexes[3]][$indexes[4]][$indexes[5]] = $values[1];

edited Jun 20, 2011 at 14:03

answered Jun 20, 2011 at 13:56

SteeveDroz

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1 Comment

Ferdinand Beyer Over a year ago

explode() can't handle regular expressions, so explode('_+') won't split on __.

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