How to add array if key value is same - php

Question

Hi i having difficulty to trace an multi dimensional array.
[
0 => array:7 [
"date" => "2016-01-19"
"placement_id" => 1
"requests" => 18
"revenue" => 1
],
1 => array:7 [
"date" => "2016-01-19"
"placement_id" => 1
"requests" => 2
"revenue" => 0.2
]
];
if placement_id are same i want resulted array:
1 => array:7 [
"date" => "2016-01-19"
"placement_id" => 1
"requests" => 20
"revenue" => 1.2
]

Answer 1

The requirement is to produce an output array that has:
Items with the same 'placement_id' having the 'requests' and revenue summed.
The key of the entry in the output array will be be the 'placement_id'.
That means that the output array will be smaller that the input array.
I decided to use the array_reduce function. There is no special reason, foreach loops work fine. It isn't any more efficient. It is just different.
The important point about array_reduce is that the $carry (accumulator) can be an array...
Working example at Eval.in
The code:
$outArray = array();
$outArray = array_reduce($src,
function($carry, $item) { // accumulate values if possible
$carryKey = $item['placement_id']; // array key
if (isset($carry[$carryKey])) { // accumulate values
$carry[$carryKey]['requests'] += $item['requests'];
$carry[$carryKey]['revenue'] += $item['revenue'];
} else { // is new - add to the output...
$carry[$carryKey] = $item;
}
return $carry;
},
array() /* accumulator ($carry) is an internal variable */);
Output Array:
array (2) [
'1' => array (4) [
'date' => string (10) "2016-01-19"
'placement_id' => integer 1
'requests' => integer 20
'revenue' => float 1.2
]
'666' => array (4) [
'date' => string (10) "2016-04-01"
'placement_id' => integer 666
'requests' => integer 266
'revenue' => float 666.20000000000005
]
]
Test Data:
$src = array(
0 => array(
"date" => "2016-01-19",
"placement_id" => 1,
"requests" => 18,
"revenue" => 1,
),
1 => array(
"date" => "2016-04-01",
"placement_id" => 666,
"requests" => 266,
"revenue" => 666.2,
),
2 => array(
"date" => "2016-01-19",
"placement_id" => 1,
"requests" => 2,
"revenue" => 0.2,
),
);

Answer 2

Taking that $arr parameter is the array that you show, we could create a function like this to look for duplicates ids and aggregate them. The $output array will return the results.
public function checkArray($arr) {
$output = array();
$deleted = array();
foreach($arr as $key => $value){
if (!in_array($key, $deleted)) {
$entry = array();
$entry['date'] = $value['date'];
$entry['placement_id'] = $value['placement_id'];
$entry['requests'] = $value['requests'];
$entry['revenue'] = $value['revenue'];
foreach($arr as $key2 => $value2){
if($key != $key2 && $value['placement_id'] == $value2['placement_id']){
$entry['requests'] += $value2['requests'];
$entry['revenue'] += $value2['revenue'];
$deleted[] = $key2;
}
}
$output[] = $entry;
}
}
return $output;
}