php转换成json数据格式?

Question

{ "programmers": [ { "firstName": "Brett", "lastName":"McLaughlin", "email": "aaaa" }, { "firstName": "Jason", "lastName":"Hunter", "email": "bbbb" }, { "firstName": "Elliotte", "lastName":"Harold", "email": "cccc" }],"authors": [ { "firstName": "Isaac", "lastName": "Asimov", "genre": "science fiction" }, { "firstName": "Tad", "lastName": "Williams", "genre": "fantasy" }, { "firstName": "Frank", "lastName": "Peretti", "genre": "christian fiction" } ], "musicians": [ { "firstName": "Eric", "lastName": "Clapton", "instrument": "guitar" }, { "firstName": "Sergei", "lastName": "Rachmaninoff", "instrument": "piano" } ] } 这样的数据格式是怎么样转换的我从数据库查出来的数据直接转换的话是[{ "firstName": "Eric", "lastName": "Clapton", "instrument": "guitar" },{ "firstName": "Sergei", "lastName": "Rachmaninoff", "instrument": "piano" }]这样的！因为是分开查询三个表 ，把它组成一条json数据，应该怎么去写

Answer 1

　json和php数组 格式的互相转换，参考如下：
　　$php_json = json_encode($json_arr); //把php数组格式转换成 json 格式的数据
　　echo $php_json;
　　$php_json = json_decode($php_json); //再把json格式的数据转换成php数组
　　print_r($php_json);

　　json数组
　　$json = '[{"id":"22","name":"33","descn":"44"}]'; //json格式的数组转换成 php的数组
　　$arr = (Array)json_decode($json);
　　echo $arr[0]->id; //用对象的方式访问