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<?php $date = time(); $result[0] = date('Y-m-01'); for ($i = 1; $i < 12; $i++) { $date = strtotime('next month', $date); $result[$i] = date('Y-m-d', $date); } var_dump($result);
Output for 5.6.38, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.25, 7.3.0 - 7.3.12, 7.4.0
array(12) { [0]=> string(10) "2017-06-01" [1]=> string(10) "2017-07-29" [2]=> string(10) "2017-08-29" [3]=> string(10) "2017-09-29" [4]=> string(10) "2017-10-29" [5]=> string(10) "2017-11-29" [6]=> string(10) "2017-12-29" [7]=> string(10) "2018-01-29" [8]=> string(10) "2018-03-01" [9]=> string(10) "2018-04-01" [10]=> string(10) "2018-05-01" [11]=> string(10) "2018-06-01" }

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