Merge 2d array rows with same column value and sum another column

Question

I have a two-dimensional array like this:like this:

[
    ['city' => 'NewYork', 'cash' => 1000],
    ['city' => 'Philadelphia', 'cash' => 2300],
    ['city' => 'NewYork', 'cash' => 2000]
]

I'd like to sum the value cash of rows which share the same city value to form a result with the same 2d structure.

Desired result:

[
    ['city' => 'NewYork', 'cash' => 3000],
    ['city' => 'Philadelphia', 'cash' => 2300],
]

Answer 1

Try below code:

<?php

$arr = array(
        array('city' => 'NewYork', 'cash' => '1000'),
        array('city' => 'Philadelphia', 'cash' => '2300'),
        array('city' => 'NewYork', 'cash' => '2000'),
    );

$newarray = array();
foreach($arr as $ar)
{
    foreach($ar as $k => $v)
    {
        if(array_key_exists($v, $newarray))
            $newarray[$v]['cash'] = $newarray[$v]['cash'] + $ar['cash'];
        else if($k == 'city')
            $newarray[$v] = $ar;
    }
}

print_r($newarray);

Output:

Array
(
    [NewYork] => Array
        (
            [city] => NewYork
            [cash] => 3000
        )

    [Philadelphia] => Array
        (
            [city] => Philadelphia
            [cash] => 2300
        )

)

Demo:
http://3v4l.org/D8PME