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<?php ini_set('display_errors', 1); error_reporting(E_ALL); $db_results = [ ['cat' => 1, 'id' => 1], ['cat' => 1, 'id' => 2], ['cat' => 2, 'id' => 3], ['cat' => 1, 'id' => 4] ]; $category_map = []; foreach ( $db_results as $row ) { $category_map[ $row['cat'] ][ $row['id'] ] = $row; } print_r($category_map);
Output for 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.7 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.7
Array ( [1] => Array ( [1] => Array ( [cat] => 1 [id] => 1 ) [2] => Array ( [cat] => 1 [id] => 2 ) [4] => Array ( [cat] => 1 [id] => 4 ) ) [2] => Array ( [3] => Array ( [cat] => 2 [id] => 3 ) ) )
Output for 4.4.2 - 4.4.9, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29
Parse error: syntax error, unexpected '[' in /in/v8lS9 on line 6
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.3.11, 4.4.0 - 4.4.1, 5.0.0 - 5.0.5
Parse error: parse error, unexpected '[' in /in/v8lS9 on line 6
Process exited with code 255.
Output for 4.3.2 - 4.3.4
Parse error: parse error in /in/v8lS9 on line 6
Process exited with code 255.

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