php json函数

<span>$arr</span>=<span>array</span>(<span>"A"</span>=><span>"a"</span>,<span>"B"</span>=><span>"b"</span>,<span>"C"</span>=><span>"c"</span>,<span>"D"</span>=><span>"d"</span>);
 <span>echo</span> json_encode(<span>$arr</span>);


 output:{<span>"A"</span>:<span>"a"</span>,<span>"B"</span>:<span>"b"</span>,<span>"C"</span>:<span>"c"</span>,<span>"D"</span>:<span>"d"</span>} 

<span>$arr</span>=<span>'{"A":"a","B":"b","C":"c","D":"d"}'</span>;
 var_dump(json_decode(<span>$arr</span>));
 var_dump(json_decode(<span>$arr</span>,<span>true</span>));
 output:

 object(stdClass)[<span>1</span>]
  <span>public</span><span>'A'</span> => string <span>'a'</span> (length=<span>1</span>)
  <span>public</span><span>'B'</span> => string <span>'b'</span> (length=<span>1</span>)
  <span>public</span><span>'C'</span> => string <span>'c'</span> (length=<span>1</span>)
  <span>public</span><span>'D'</span> => string <span>'d'</span> (length=<span>1</span>)

<span>array</span> (size=<span>4</span>)
  <span>'A'</span> => string <span>'a'</span> (length=<span>1</span>)
  <span>'B'</span> => string <span>'b'</span> (length=<span>1</span>)
  <span>'C'</span> => string <span>'c'</span> (length=<span>1</span>)
  <span>'D'</span> => string <span>'d'</span> (length=<span>1</span>)