How to group subarrays by a column value?

Question

I have the following array

Array
(
    [0] => Array
        (
            [id] => 96
            [shipping_no] => 212755-1
            [part_no] =&         


        

Answer 1

I just threw this together, inspired by .NET LINQ

<?php

// callable type hint may be "closure" type hint instead, depending on php version
function array_group_by(array $arr, callable $key_selector) {
  $result = array();
  foreach ($arr as $i) {
    $key = call_user_func($key_selector, $i);
    $result[$key][] = $i;
  }  
  return $result;
}

 $data = array(
        array(1, "Andy", "PHP"),
        array(1, "Andy", "C#"),
        array(2, "Josh", "C#"),
        array(2, "Josh", "ASP"),
        array(1, "Andy", "SQL"),
        array(3, "Steve", "SQL"),
    );

$grouped = array_group_by($data, function($i){  return $i[0]; });

var_dump($grouped);

?>

And voila you get

array(3) {
  [1]=>
  array(3) {
    [0]=>
    array(3) {
      [0]=>
      int(1)
      [1]=>
      string(4) "Andy"
      [2]=>
      string(3) "PHP"
    }
    [1]=>
    array(3) {
      [0]=>
      int(1)
      [1]=>
      string(4) "Andy"
      [2]=>
      string(2) "C#"
    }
    [2]=>
    array(3) {
      [0]=>
      int(1)
      [1]=>
      string(4) "Andy"
      [2]=>
      string(3) "SQL"
    }
  }
  [2]=>
  array(2) {
    [0]=>
    array(3) {
      [0]=>
      int(2)
      [1]=>
      string(4) "Josh"
      [2]=>
      string(2) "C#"
    }
    [1]=>
    array(3) {
      [0]=>
      int(2)
      [1]=>
      string(4) "Josh"
      [2]=>
      string(3) "ASP"
    }
  }
  [3]=>
  array(1) {
    [0]=>
    array(3) {
      [0]=>
      int(3)
      [1]=>
      string(5) "Steve"
      [2]=>
      string(3) "SQL"
    }
  }
}

Answer 2

Expanding on @baba's answer, which I like, but creates a more complex three level deep multi-dimensional (array(array(array))):

$group = array();
 foreach ( $array as $value ) {
   $group[$value['id']][] = $value; 
 }

// output only data from id 96
foreach ($group as $key=>$value) { //outer loop
 foreach ($value as $k=>$v){ //inner loop
  if($key==96){ //if outer loop is equal to 96 (could be variable)
   for ($i=0;$i<count($k);$i++){ //iterate over the inner loop
        printf($key.' has a part no. of '.$v['part_no'].' and shipping no. of '.$v['shipping_no'].'<br>');
   }
 }
}
 }

Will output:

96 has a part no. of reterty and shipping number of 212755-1

96 has a part no. of dftgtryh and shipping number of 212755-1

Answer 3

function groupeByPHP($array,$indexUnique,$assoGroup,$keepInOne){
$retour = array();
$id = $array[0][$indexUnique];
foreach ($keepInOne as $keep){
    $retour[$id][$keep] = $array[0][$keep];
}
foreach ($assoGroup as $cle=>$arrayKey){
    $arrayGrouped = array();
        foreach ($array as $data){
            if($data[$indexUnique] != $id){
                $id = $data[$indexUnique];
                foreach ($keepInOne as $keep){
                    $retour[$id][$keep] = $data[$keep];
                }
            }
            foreach ($arrayKey as $val){
                $arrayGrouped[$val] = $data[$val];
            }
            $retour[$id][$cle][] = $arrayGrouped;
            $retour[$id][$cle] = array_unique($retour[$id][$cle],SORT_REGULAR);
        }
}
return  $retour;
}

Try this function

groupeByPHP($yourArray,'id',array('desc'=>array('part_no','packaging_type')),array('id','shipping_no')) 

Answer 4

This should group an associative array Ejm Group By Country

function getGroupedArray($array, $keyFieldsToGroup) {   
    $newArray = array();

    foreach ($array as $record) 
        $newArray = getRecursiveArray($record, $keyFieldsToGroup, $newArray);

    return $newArray;
}
function getRecursiveArray($itemArray, $keys, $newArray) {
    if (count($keys) > 1) 
        $newArray[$itemArray[$keys[0]]] = getRecursiveArray($itemArray,    array_splice($keys, 1), $newArray[$itemArray[$keys[0]]]);
    else
        $newArray[$itemArray[$keys[0]]][] = $itemArray;

    return $newArray;
}

$countries = array(array('Country'=>'USA', 'State'=>'California'),
                   array('Country'=>'USA', 'State'=>'Alabama'),
                   array('Country'=>'BRA', 'State'=>'Sao Paulo'));

$grouped = getGroupedArray($countries, array('Country'));

Answer 5

for($i = 0 ; $i < count($arr)  ; $i++ )
{
    $tmpArr[$arr[$i]['id']] = $arr[$i]['id'];
}
$vmpArr = array_keys($tmpArr);
print_r($vmpArr);

Answer 6

I think this works better in PHP 5.5+

$IdVar = array_column($data, 'id');