php数组 json转换

php数组转json数组：

$a[0] = 'a';
$a[1] = 'b';
$a[2] = 'c';
echo json_encode($a);

结果为：
json数组  ["a","b","c"]

php数组转json对象

$a = [1=>'a',2=>'b',3=>'c'];
echo json_encode($a);
 
执行结果为：
 {"1":"a","2":"b","3":"c"}

php json数组 转 数组
<?php
$a = '["a","b","c"]';
var_dump(json_decode($a,true));

输出结果为：
    array(3) {
      [0]=>
      string(1) "a"
      [1]=>
      string(1) "b"
      [2]=>
      string(1) "c"
    }
?>

php json对象转 php数组
<?php
$a = '{"a":"11","b":"22","c":"33"}';
var_dump(json_decode($a,true));

执行结果：
array(3) {
  ["a"]=>
  string(2) "11"
  ["b"]=>
  string(2) "22"
  ["c"]=>
  string(2) "33"
}
?>