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<?php $array = [ ["year"=>"2016","numb"=>1], ["year"=>"2016","numb"=>3], ["year"=>"2017","numb"=>3], ["year"=>"2016","numb"=>1], ["year"=>"2018","numb"=>2] ]; $newArray = []; $years = array_column($array, "year"); foreach($years as $year){ $year_filtered = array_filter($array, function($d)use($year){ return intval($d["year"]) <= intval($year);}); $total = array_sum(array_column($year_filtered, "numb")); $newArray[$year] = $total; } print_r($newArray);
Output for 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.26, 8.4.1 - 8.4.13
Array ( [2016] => 5 [2017] => 8 [2018] => 10 )

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