The input array:
[
[1 => 2],
[1 => 2],
[2 => 1],
[3 => 1],
]
I want this output:
[
[1 => 4],
[2 => 1],
[3 => 1],
]
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Is there always only one element inside each sub array?Ja͢ck– Ja͢ck2014-03-26 07:57:21 +00:00Commented Mar 26, 2014 at 7:57
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I want [0] => Array ( [1] => 2 ) [1] => Array ( [1] => 2 ) as [0] => Array ( [1] => 4 )Happy– Happy2014-03-26 07:57:52 +00:00Commented Mar 26, 2014 at 7:57
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3Why does your result have a separate sub-array for each key? Why not a single associative array with all the results?Barmar– Barmar2014-03-26 07:58:11 +00:00Commented Mar 26, 2014 at 7:58
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2Happy you are really making us Sad.Shankar Narayana Damodaran– Shankar Narayana Damodaran2014-03-26 07:59:04 +00:00Commented Mar 26, 2014 at 7:59
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3 Answers
Seems like a good case for array_reduce():
$res = array_chunk(array_reduce($arr, function(&$current, $item) {
foreach ($item as $key => $value) {
if (!isset($current[$key])) {
$current[$key] = 0;
}
$current[$key] += $value;
}
return $current;
}, []), 1, true);
For the final result I'm using array_chunk(); it takes an array and creates single element sub arrays of each element.
Comments
$result = array();
foreach ($input as $subarray) {
foreach ($subarray as $key => $value) {
if (isset($result[$key])) {
$result[$key][$key] += $value;
} else {
$result[$key] = array($key => $value);
}
}
}
$result = array_values($result); // Convert from associative array to indexed array
Comments
By identifying unique groups and only pushing references into the result array, you can avoid needing to reindex the result after the loop. Demo
$result = [];
foreach ($array as $row) {
$k = key($row);
if (!isset($ref[$k])) {
$ref[$k] = 0;
$result[][$k] =& $ref[$k];
}
$ref[$k] += $row[$k];
}
var_export($result);
Output:
array (
0 =>
array (
1 => 4,
),
1 =>
array (
2 => 1,
),
2 =>
array (
3 => 1,
),
)
Comments
