PHP json_encode()函数使用

  <?php
 $tmp = array();
 echo json_encode($tmp); //打印 []
 echo "\n";
 echo json_encode($tmp,JSON_FORCE_OBJECT); //打印 {}
 echo "\n";

 $tmp = array('a','b');
 echo json_encode($tmp); //打印 ["a","b"]
 echo "\n";
 echo json_encode($tmp,JSON_FORCE_OBJECT); //打印 {"0":"a","1":"b"}
 echo "\n";

 $tmp = array(0=>'a',3=>'b');
 echo json_encode($tmp); //打印 {"0":"a","3":"b"}
 echo "\n";

 $tmp = array(0=>'a',1=>'b');
 echo json_encode($tmp); //打印 ["a","b"]
 echo "\n";
 echo json_encode($tmp,JSON_FORCE_OBJECT); //打印 {"0":"a","1":"b"}
 echo "\n";
 ?>

结果：