How to count all values in a multidimensional array? - php

Question

I have tried solutions to many similar questions, but they all seem to give me a count for each array. So I have the following array:
Array
(
[1] => Array
(
[0] => 1
[1] => 12
[2] => 2
)
[2] => Array
(
[0] => 1
[1] => 13
[2] => 3
)
[3] => Array
(
[0] => 1
[1] => 12
[2] => 2
)
[4] => Array
(
[0] => 1
)
[5] => Array
(
[0] => 1
)
)
I am trying to count the duplicates across all arrays. So the output should show:
Five 1's
Two 12's
One 13
Two 2's
At the moment I am trying:
foreach($data as $key => $row) {
print_r(array_count_values($row));
}
Which outputs the counts for each individual array
Array
(
[1] => 1
[12] => 1
[2] => 1
)
Array
(
[1] => 1
[13] => 1
[3] => 1
)
Array
(
[1] => 1
[12] => 1
[2] => 1
)
Array
(
[1] => 1
)
Array
(
[1] => 1
)
I have also tried this:
foreach ($data as $key => $row) {
$counts = array_count_values(array_column($data, $key));
var_dump($counts);
}
Which seems to miss a lot of information, like the count of the 1's
array(2) {
[12]=>
int(2)
[13]=>
int(1)
}
array(2) {
[2]=>
int(2)
[3]=>
int(1)
}
array(0) {
}
array(0) {
}
array(0) {
}
As a note, the initial array keys will not always be sequential, as this represents a row number. So this array may contain rows 1, 2, 5, 6, 7 etc.
How would I go about counting all duplicates together?

Answer 1

Since your array is not flattened, you will need to visit each value and increment unless you want to call merging functions.
Code: (Demo)
$array = [
1 => [1, 12, 2],
2 => [1, 13, 3],
3 => [1, 12, 2],
4 => [1],
5 => [1]
];
// make the generated value available outside of function scope
// \-------------------------------v--------------------------/
array_walk_recursive($array, function($v)use(&$output) { // visit each leafnode
if (isset($output[$v])) { // check if the key has occurred before
++$output[$v]; // increment
} else {
$output[$v] = 1; // declare as 1 on first occurrence
}
});
var_export($output);
Output:
array (
1 => 5,
12 => 2,
2 => 2,
13 => 1,
3 => 1,
)
Or, non-recursively:
foreach ($array as $row) {
foreach ($row as $v) {
if (isset($output[$v])) { // check if the key has occurred before
++$output[$v]; // increment
} else {
$output[$v] = 1; // declare as 1 on first occurrence
}
}
}
Or, a functional one-liner to flatten then count:
var_export(array_count_values(array_reduce($array, 'array_merge', array())));
Or, a functional one-liner with the splat operator to flatten then count:
var_export(array_count_values(array_merge(...$array)));

Answer 2

You can do this quite easily by using an accumulator array and iterating all the elements:
$result = [];
foreach ($data as $row) {
foreach($row as $value) {
$result[$value] = isset($result[$value]) ? $result[$value] + 1 : 1;
}
}
var_dump($result);

Answer 3

You can use call_user_func_array to merge all the individual arrays, and then array_count_values on that result:
$data = array
(array(1, 12, 2),
array(1, 13, 3),
array(1, 12, 2),
array(1),
array(1)
);
print_r(array_count_values(call_user_func_array('array_merge', $data)));
Output:
Array
(
[1] => 5
[12] => 2
[2] => 2
[13] => 1
[3] => 1
)