如何在PHP中对多维数组进行排序[重复]

Question

This question already has an answer here:

• How can I sort arrays and data in PHP? 10 answers

I have CSV data loaded into a multidimensional array. In this way each "row" is a record and each "column" contains the same type of data. I am using the function below to load my CSV file.

function f_parse_csv($file, $longest, $delimiter)
{
  $mdarray = array();
  $file    = fopen($file, "r");
  while ($line = fgetcsv($file, $longest, $delimiter))
  {
    array_push($mdarray, $line);
  }
  fclose($file);
  return $mdarray;
}

I need to be able to specify a column to sort so that it rearranges the rows. One of the columns contains date information in the format of Y-m-d H:i:s and I would like to be able to sort with the most recent date being the first row.

</div>

Answer 1

You can use array_multisort()

Try something like this:

foreach ($mdarray as $key => $row) {
    // replace 0 with the field's index/key
    $dates[$key]  = $row[0];
}

array_multisort($dates, SORT_DESC, $mdarray);

For PHP >= 5.5.0 just extract the column to sort by. No need for the loop:

array_multisort(array_column($mdarray, 0), SORT_DESC, $mdarray);