How PHP implements the ordering of two-dimensional associative arrays

How PHP implements the ordering of two-dimensional associative arrays
For example, arrays are like this:

  $example = Array (Array (' B ' =>7, ' RSD ' =>6, ' GDD ' =>3),
                    Array (' d ' =>5, ' ess ' =>8, ' FFS ' =>5),
            Array (' C ' =>2, ' SDV ' =>5, ' VFS ' =>6),
            Array (' A ' =>8, ' HDS ' =>4, ' RFS ' =>9));

Do not use PHP system functions, with Uasort () or Uksort (), how to write a custom function to pass in?
function Compare ($X, $Y)
So with Uasort ($example, ' compare '),
How should this compare be written?

Two-dimensional arrays that are not associative I know how to write compare,

  function Compare ($x, $y)
  {
  if ($x [0] = = $y [0])
    return 0;
  ElseIf ($x [0] < $y [0])
    return-1;
  Else
    return 1;
  }

------Solution--------------------
Manual Array_multisort
See Example # #
------Solution--------------------
Example #4 Sorting the results of a database


In this example, each cell in the data array represents a row in a table. This is a data collection of typical database records.


The data in the example is as follows:


Volume
------Solution--------------------
Edition
-------+--------
67
------Solution--------------------
2
86
------Solution--------------------
1
85
------Solution--------------------
6
98
------Solution--------------------
2
86
------Solution--------------------
6
67
------Solution--------------------
7


The data is all stored in an array named data. This is usually done by looping the results from the database, such as MYSQL_FETCH_ASSOC ().


$data [] = Array (' volume ' = +, ' edition ' = 2);
$data [] = Array (' volume ' = +, ' edition ' = 1);
$data [] = Array (' volume ' = =, ' edition ' = 6);
$data [] = Array (' volume ' = = 98, ' edition ' = 2);
$data [] = Array (' volume ' = +, ' edition ' = 6);
$data [] = Array (' volume ' = +, ' edition ' = 7);
?>


In this example, the volume is sorted in descending order, and the edition in ascending order.


Now that you have an array with rows, but Array_multisort () requires an array of columns, so use the following code to get the columns and sort them.


Get a list of columns
foreach ($data as $key = = $row) {
$volume [$key] = $row [' volume '];
$edition [$key] = $row [' Edition '];
}

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