How to concatenate array rows?

Question

PHP

The database contains entries in the style:

Array ( [id] => 1 [data] => 03.03.15 09:28:46 [latitude] => 49.23342514 [longitude] => 28.40869522 [ppm] => ppm= ) 
Array ( [id] => 2 [data] => 03.03.15 09:28:46 [latitude] => 49.23342514 [longitude] => 28.40869522 [ppm] => 701 ) 
Array ( [id] => 3 [data] => 03.03.15 09:28:47 [latitude] => 49.23335648 [longitude] => 28.40859604 [ppm] => ppm ) 
Array ( [id] => 4 [data] => 03.03.15 09:28:47 [latitude] => 49.23335648 [longitude] => 28.40859604 [ppm] => =679 ) 
Array ( [id] => 5 [data] => 03.03.15 09:28:48 [latitude] => 49.23325729 [longitude] => 28.40863609 [ppm] => pp ) 
Array ( [id] => 6 [data] => 03.03.15 09:28:48 [latitude] => 49.23325729 [longitude] => 28.40863609 [ppm] => m=65 ) 
Array ( [id] => 7 [data] => 03.03.15 09:28:48 [latitude] => 49.23325729 [longitude] => 28.40863609 [ppm] => 6 )

The output should be something like this:

Array ( [id] => 1 [data] => 03.03.15 09:28:46 [latitude] => 49.23342514 [longitude] => 28.40869522 [ppm] => ppm=701 ) 
Array ( [id] => 3 [data] => 03.03.15 09:28:47 [latitude] => 49.23335648 [longitude] => 28.40859604 [ppm] => ppm=679) 
Array ( [id] => 5 [data] => 03.03.15 09:28:48 [latitude] => 49.23325729 [longitude] => 28.40863609 [ppm] => ppm=656 )

those. combine what is in the ppm column by the common data column
how to implement this? can't think of

Answer 1

And it's even easier - to store classes at once or filter at the sampling stage.

<?php

class GeoPosition {
  private $data;

  public function __construct(array $data)
  {
    $this->data = $data;
  }

  public function getData()
  {
    return $this->data;
  }

  public function __toString()
  {
    return $data['data'];
  }
}

/** @var array[] $dbResponse */
$normalizedData = array_map(function (array $geoPosition) {
  return new GeoPosition($geoPosition);
}, $dbResponse);

$filteredData = array_unique($normalizedData, SORT_STRING);
$denormalized = array_map(function (GeoPosition $geoPosition) {
  return $geoPosition->getData();
}, $filteredData);

Answer 2

if(($length = count($arr)) > 1)
    for($i = 1, $row = $arr[0]; $i < $length; $i++) {
      if($row['data'] === $arr[$i]['data'])
        $arr[$i]['ppm'] = $row['ppm'] . $arr[$i]['ppm'];
      else
        $row = $arr[$i];
    }

Answer 3

immediately normal database design ...

Answer 4

array_unique() ?

Answer 5

// $array = [ ['id' => 1...
$result = [];
foreach ($array as $item) {
    if (isset($result[$item['data']])) {
        $result[$item['data']]['ppm'] .= $item['ppm'];
    } else {
        $result[$item['data']] = $item;
    }
}
$result = array_values($result);