Sum all values in a 2d array

Question

How can I sum all of the values in an array of arrays?

Sample array:

[
    [0],
    [0],
    [1, 6, 0]
]

Desired output: 7

Answer 1

echo array_sum(
    call_user_func_array('array_merge', $array)
);
//or
echo array_sum(
    array_map('array_sum', $array)
);