PHP - 来自json的打印对象键

sorry i got a stupid question i know but i'm in trouble, i'm unable to print the Countries from this array:

$array =   json_decode('[
   {
       "Afghanistan": {
           "lang": "en",
           "browser_code": []
       }
   },
   {
       "Albania": {
           "lang": "en",
           "browser_code": []
       }
   },
   {
       "Algeria": {
           "lang": "en",
           "browser_code": []
       }
   }
]');

my try:

foreach($array as $key){
 foreach($key as $k){
  echo $k;
}
}

i tryed in many ways using a foreach(){} loop but i'm in trouble with the logic, i just have to print out:

Afghanistan, Algeria, Algeria

Any clue?

$arrJson = json_decode('[
   {
       "Afghanistan": {
           "lang": "en",
           "browser_code": []
       }
   },
   {
       "Albania": {
           "lang": "en",
           "browser_code": []
       }
   },
   {
       "Algeria": {
           "lang": "en",
           "browser_code": []
       }
   }
]');
foreach($arrJson as $key=>$val){
  foreach($val as $k=>$v){
    echo $k." , ";
  }
}

Live demo

Try this:

foreach($array as $item) {
    foreach ($item as $countryName => $countryData) {
        echo $countryName; // Should be "Afghanistan"
        echo $countryData; // Should be array('lang' => 'en', 'browser_code' => array())
    }
}