php json_encode()

$b = array();

echo  "Empty array output as array: " ,  json_encode ( $b ),  "\n" ;
echo  "Empty array output as object: " ,  json_encode ( $b ,  JSON_FORCE_OBJECT ),  "\n\n" ;

$c  = array(array( 1 , 2 , 3 ));

echo  "Non-associative array output as array: " ,  json_encode ( $c ),  "\n" ;
echo  "Non-associative array output as object: " ,  json_encode ( $c ,  JSON_FORCE_OBJECT ),  "\n\n" ;

$d  = array( 'foo'  =>  'bar' ,  'baz'  =>  'long' );

echo  "Associative array always output as object: " ,  json_encode ( $d ),  "\n" ;

echo "Associative array always output as object: ", json_encode($d, JSON_FORCE_OBJECT), "\n\n";

Empty array output as array: []
Empty array output as object: {}

Non-associative array output as array: [[1,2,3]]
Non-associative array output as object: {"0":{"0":1,"1":2,"2":3}}

Associative array always output as object: {"foo":"bar","baz":"long"}
Associative array always output as object: {"foo":"bar","baz":"long"}

$a = array('',"'bar'",'"baz"','&blong&', "\xc3\xa9");

echo "Normal: ",  json_encode($a), "\n";
echo "Tags: ",    json_encode($a, JSON_HEX_TAG), "\n";
echo "Apos: ",    json_encode($a, JSON_HEX_APOS), "\n";
echo "Quot: ",    json_encode($a, JSON_HEX_QUOT), "\n";
echo "Amp: ",     json_encode($a, JSON_HEX_AMP), "\n";
echo "Unicode: ", json_encode($a, JSON_UNESCAPED_UNICODE), "\n";
echo "All: ",     json_encode($a, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_QUOT | JSON_HEX_AMP | JSON_UNESCAPED_UNICODE), "\n\n";

Normal: ["","'bar'","\"baz\"","&blong&","\u00e9"]
Tags: ["\u003Cfoo\u003E","'bar'","\"baz\"","&blong&","\u00e9"]
Apos: ["","\u0027bar\u0027","\"baz\"","&blong&","\u00e9"]
Quot: ["","'bar'","\u0022baz\u0022","&blong&","\u00e9"]
Amp: ["","'bar'","\"baz\"","\u0026blong\u0026","\u00e9"]
Unicode: ["","'bar'","\"baz\"","&blong&","é"]
All: ["\u003Cfoo\u003E","\u0027bar\u0027","\u0022baz\u0022","\u0026blong\u0026","é"]