Question

Given my Array

array [0]
    fielda: cca
    fieldb: my value b
    fieldc: my value c
    fieldd: my value d

array [1]
    fielda: cca
    fieldb: my value b
    fieldc: my value c
    fieldd: my value d

array [2]
    fielda: cca
    fieldb: my value b
    fieldc: my value c
    fieldd: my value d

array [3]
    fielda: ccb
    fieldb: my value b
    fieldc: my value c
    fieldd: my value d

array [4]
    fielda: ccb
    fieldb: my value b
    fieldc: my value c
    fieldd: my value d

Is there a simple way to restructure it so that fielda is grouped like so

array [0]
    fielda: cca
        array [0]
            fieldb: my value b
            fieldc: my value c
            fieldd: my value d
        array [1]           
            fieldb: my value b
            fieldc: my value c
            fieldd: my value d
        array [2]                   
            fieldb: my value b
            fieldc: my value c
            fieldd: my value d
        array [3]                   

array [1]
    fielda: ccb
        array [0]
            fieldb: my value b
            fieldc: my value c
            fieldd: my value d
        array [1]           
            fieldb: my value b
            fieldc: my value c
            fieldd: my value d

Answer 1

Maybe there’s a simpler way, but this should work for you:

$new_array = array();
foreach ($array as $values) // $array is your original array
{
    $new_array[array_shift($values)][] = $values;
}
print_r($new_array);

DEMO: http://codepad.org/M26yBLL4