var = [
{
'id_a' => '1',
'id_b' => '5',
'value_x' => '10'
'value_y' => '5'
},
{
'id_a' => '2',
'id_b' => '3',
'value_x' => '20'
'value_y' => '10'
},
{
'id_a' => '2',
'id_b' => '3',
'value_x' => '30'
'value_y' => '20'
},
{
'id_a' => '3',
'id_b' => '7',
'value_x' => '15'
'value_y' => '15'
}
]