Php декодировать json

 $bfbf = json_decode($response); 
printf( "<p>Ответ на Ваш запрос: " .$bfbf->['username']. "</p>");

<?php
$json = '[{"user_id":"6670639","username":"narnia3028","count300":"2330537","count100":"499125","count50":"73499","playcount":"12326","ranked_score":"1870981924","total_score":"10246304958","pp_rank":"96674","level":"97.2439","pp_raw":"1915.86","accuracy":"95.25959014892578","count_rank_ss":"3","count_rank_s":"93","count_rank_a":"108","country":"RU","pp_country_rank":"6766","events":[]}]';
var_dump($json);
$aj = json_decode(substr($json,1,-1),true);
var_dump($aj);
var_dump($aj['username']);

$aj = json_decode(substr($response,1,-1),true);
            //var_dump($aj);
            printf( "<p>Ответ на Ваш запрос: " .var_dump($aj['username']). "</p>");

$aj = json_decode(substr($response,1,-1),true);
echo "<p>Ответ на Ваш запрос: " .$aj['username']. "</p>";

$bfbf = json_decode($response); 
printf( "<p>Ответ на Ваш запрос: " .$bfbf[0]->username. "</p>");

$bfbf = json_decode($response, true); 
printf( "<p>Ответ на Ваш запрос: %s</p>", $bfbf[0]['username']);