Group array by keys value

I have searched around and I am at my wits end so I will make this easy. This is what I have in a print_r:

Array
(
    [0] => Array
        (
            [name] => client interaction
            [y] => 2.7
        )

    [1] => Array
        (
            [name] => client interaction
     开发者_高级运维       [y] => 0.1
        )

    [2] => Array
        (
            [name] => project planning
            [y] => 0.1
        )

    [3] => Array
        (
            [name] => client interaction
            [y] => 5.9
        )

)

And this is what I want it to be:

Array
(
    [0] => Array
        (
            [name] => client interaction
            [y] => 8.7
        )

    [1] => Array
        (
            [name] => project planning
            [y] => 0.1
        )

)

Is it absolutely necessary that your desired array use numeric indeces? If I were to do this I would do it this way (not the same as your desired array though)

$newArray = array();
foreach($array as $item)
{
  if(!isset($newArray[$item["name"]]))
    $newArray[$item["name"]] = 0;

  $newArray[$item["name"]] += $item["y"];
}

This will give you an array of this structure:

Array
(
  [client interaction] => 8.7
  [project planning] => 0.1
)

To get the keys back you simply use the second form of the foreach loop

foreach($newArray as $name => $y)

$name will contain the name and $y the y in your original array.

$hash = array();
foreach ($sourceArray as $key=>$value) {
   $y = 0;
   if (isset($hash{$value{'name'}})) {
      $y = $hash{$value{'name'}};
   }

   $hash{$value{'name'}} = $y + $value{'y'};
}

$result = array();
foreach ($hash as $key => $value) {
  $result[] = array( 'name' => $key, 'value' => $value );
}
print_r($result);

The last loop is just to get $hash into the exact format you specified.

Explanation:

$hash

Is a temporary structure used to compute the sums for each unique name.

foreach ($sourceArray as $key=>$value) {

This goes through your original array ($sourceArray) and pulls out each element.

   $y = 0;

Initializes a variable to store the current sum that belongs with that name.

   if (isset($hash{$value{'name'}})) {

Checks to see if a value has already been stored in $hash for the given name.

      $y = $hash{$value{'name'}};
   }

Sets $y to the previously calculated sum for the given name, if there was one.

   $hash{$value{'name'}} = $y + $value{'y'};
}

Stores the sum for the given name into our temporary structure $hash.

 $result = array();
    foreach ($hash as $key => $value) {
      $result[] = array( 'name' => $key, 'value' => $value );
    }

converts $hash to the format you desired.

The empy []'s in $result[] = ... add the right hand side of the expression to the end of the $result array.

$mixed = array(); // Should contain your array shown above
$groups = array();
$newArray = array(); // Will contain your new array
$counter = 0;

foreach( $mixed as $mix )
{
    if ( isset($groups[$mix['name']]) )
    {
        $newArray[$groups[$mix['name']]]['y'] += $mix['y'];
    }
    else
    {
        $groups[$mix['name']] = $counter;
        $newArray[] = $mix;
        $counter++;
    }
}

http://codepad.org/EjdHxgvt