使用JSON和PHP查找子数组中的最高值条目

Question

我已经玩了几个小时了，运气不太好。

我当前的JSON看起来像这样：https://pastebin.com/TSmWFA2g

"10-10-2019 12:00AM":[ 
  { 
     "speed":33,
     "latitude":-11.2588112,
     "longitude":100.8249533
  },
  { 
     "speed":33,
     "latitude":-11.2381112,
     "longitude":100.82509
  },
  { 
     "speed":31,
     "latitude":-11.827312,
     "longitude":100.8242733
  }
],
"10-10-2019 12:01AM":[ 
  { 
     "speed":29,
     "latitude":-11.2902112,
     "longitude":100.8202849
  },
  { 
     "speed":26,
     "latitude":-11.2826432,
     "longitude":100.3760333
  }
]

我试图为每个日期查找具有最高“速度”的条目，并删除该日期下的其他条目（或使用单个条目创建一个新的数组。）>

编辑01：

我现在尝试过：

function my_sort($a,$b)
{
return $b['speed'] - $a['speed'];
}
usort($finalData,"my_sort");
echo json_encode($finalData);
这将按速度对数据进行排序，但JSON现在不包括原始JSON中的日期。

[{"speed":33,"latitude":-11.2588112,"longitude":100.82509}, 
{"speed":33,"latitude":-11.2588112,"longitude":100.82509}, 
{"speed":31,"latitude":-11.2588112,"longitude":100.82509}, 
{"speed":31,"latitude":-11.2588112,"longitude":100.82509}, 
{"speed":33,"latitude":-11.2588112,"longitude":100.82509}, 
{"speed":32,"latitude":-11.2588112,"longitude":100.82509}, 
{"speed":24,"latitude":-11.2588112,"longitude":100.82509}, 
{"speed":16,"latitude":-11.2588112,"longitude":100.82509},]

我已经玩了几个小时了，运气还不太好。我当前的JSON看起来像这样：https://pastebin.com/TSmWFA2g“ 10-10-2019 12:00 AM”：[{“ speed”：33，...

Answer 1

<?php

$data = json_decode('{
   "10-10-2019 12:00AM":[
      {
         "speed":33,
         "latitude":-11.2588112,
         "longitude":100.8249533
      },
      {
         "speed":33,
         "latitude":-11.2381112,
         "longitude":100.82509
      },
      {
         "speed":31,
         "latitude":-11.827312,
         "longitude":100.8242733
      }
   ],
   "10-10-2019 12:01AM":[
      {
         "speed":29,
         "latitude":-11.2902112,
         "longitude":100.8202849
      },
      {
         "speed":26,
         "latitude":-11.2826432,
         "longitude":100.3760333
      }
   ],
   "10-10-2019 12:02AM":[
      {
         "speed":35,
         "latitude":-11.2991112,
         "longitude":100.0129199
      },
      {
         "speed":33,
         "latitude":-11.9273112,
         "longitude":100.8734016
      },
      {
         "speed":32,
         "latitude":-11.2533212,
         "longitude":100.19229
      },
      {
         "speed":30,
         "latitude":-11.2928112,
         "longitude":100.2495099
      },
      {
         "speed":24,
         "latitude":-11.2228112,
         "longitude":100.9266033
      }
   ]
}',true);

$newArray=array();
foreach ($data as $key => $value) {
    array_multisort(array_column($value, 'speed'), SORT_DESC, $value);
    $newArray[$key]=$value[0];
}

echo "<pre>";
print_r($newArray);
echo "<pre>";
?>