$arr1 = array(
1=>array(
 'name' => 'a',
 'phone'=> '110',
),
2=>array(
 'name' => 'b',
 'phone'=> '119',
),
3=>array(
 'name' => 'a',
 'phone'=> '119',
 ),
4=>array(
 'name' => 'b',
 'phone'=> '110',
),
);

I spent 3 hours to figure it out,and fails。I wanna merge the phone values to new arrays based on the name key values。 The result like this

$arr2 = array(
 1=>array(
 'name' => 'a',
 'phone'=> array(
 1=>'110',
 2=>'119',
 ),
 ),
 2=>array(
 'name' => 'b',
 'phone'=> array(
 1=>'110',
 2=>'119',
 ),
 )
);

It looks like easy at first glimpse,but not。

$arr1 = array(
1=>array(
 'name' => 'a',
 'phone'=> '110',
),
2=>array(
 'name' => 'b',
 'phone'=> '119',
),
3=>array(
 'name' => 'a',
 'phone'=> '119',
 ),
4=>array(
 'name' => 'b',
 'phone'=> '110',
),
);

I spent 3 hours to figure it out,and fails。I wanna merge the phone values to new arrays based on the name key values。 The result like this

$arr2 = array(
 1=>array(
 'name' => 'a',
 'phone'=> array(
 1=>'110',
 2=>'119',
 ),
 ),
 2=>array(
 'name' => 'b',
 'phone'=> array(
 1=>'110',
 2=>'119',
 ),
 )
);

It's not as easy as it looks.