3v4l.org

run code in 300+ PHP versions simultaneously
<?php $f = new \DateTime('previous month'); $f->modify('first day of'); echo $f->format('Y-m-d H:i:s');
Output for 5.6.28, 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.31, 7.4.0 - 7.4.33, 8.0.0 - 8.0.12, 8.0.14 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
2015-11-01 09:01:21
Output for 7.3.32 - 7.3.33, 8.0.13
2015-11-01 08:01:21
Output for 7.0.6
2016-04-01 13:06:18
Output for 7.0.5
2016-03-01 09:10:07
Output for 7.0.4
2016-02-01 21:16:03
Output for 7.0.3
2016-02-01 22:38:01
Output for 7.0.2
2016-02-01 04:51:28
Output for 7.0.1
2016-02-01 08:00:16
Output for 7.0.0
2016-02-01 09:53:41
Output for 5.6.21
2016-04-01 16:02:27
Output for 5.6.20
2016-03-01 08:11:59
Output for 5.6.19
2016-02-01 05:23:33
Output for 5.6.18
2016-02-01 14:19:15
Output for 5.6.17
2016-02-01 01:51:36
Output for 5.6.16
2016-02-01 10:43:10
Output for 5.6.15
2016-02-01 11:32:12
Output for 5.6.14
2016-03-01 17:14:33
Output for 5.6.13
2016-03-01 17:53:30
Output for 5.6.12
2016-03-01 08:22:27
Output for 5.6.11
2016-03-01 14:48:11
Output for 5.6.10
2016-03-01 16:53:42
Output for 5.6.9
2016-03-01 22:11:02
Output for 5.6.8
2016-03-01 06:50:51
Output for 5.5.35
2016-04-01 01:37:56
Output for 5.5.34
2016-03-01 10:25:28
Output for 5.5.33
2016-02-01 08:22:35
Output for 5.5.32
2016-02-01 18:15:11
Output for 5.5.31
2016-02-01 05:00:00
Output for 5.5.30
2016-03-01 13:24:34
Output for 5.5.29
2016-03-01 08:11:21
Output for 5.5.28
2016-03-01 11:40:33
Output for 5.5.27
2016-03-01 13:19:59
Output for 5.5.26
2016-03-01 19:34:34
Output for 5.5.25
2016-03-01 02:58:31
Output for 5.5.24
2016-04-01 09:23:51

preferences:
179.4 ms | 401 KiB | 222 Q