Illegal offset type php function

Question

I got this code and I am having trouble because of illegal offset type.

function getChildren($xmlSet){

    global $output;

    if(is_object($xmlSet)){

         if(count($xmlSet->children()) > 0){

             foreach($xmlSet->children() as $i => $child){
                  if($child->getName() === "label"){
                       $output[(string)$xmlSet->attributes()['id']] = getChildren($child);
                  } else {
                       if($child->getName() === "field" || $child->getName() === "fieldset"){

                            $output[$xmlSet->attributes()['id']] = getChildren($child);
                       }
                  }
             }

Answer 1

You have this once

 $output[(string)$xmlSet->attributes()['id']] = getChildren($child);

but the second time you have

 $output[$xmlSet->attributes()['id']] = getChildren($child);

The first time did an explicit cast to a string, but the second did so implicitly, hence the warning.

Some object types, notably SimpleXMLElement for example, will return a string representation to print/echo via the magic method __toString() , but cannot stand in as regular strings. Attempts to use them as array keys will yield the illegal offset type error unless you cast them to proper strings via (string)$obj ( ref )

Answer 2

The issue is that you're trying to access an array element via a simpleXml object. Before you can access the array element you must cast it to a scalar type value.

So change this:

$output[$xmlSet->attributes()['id']] = getChildren($child);

To this:

$output[(string)$xmlSet->attributes()['id']] = getChildren($child);