3v4l.org

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<?php $year = 2013; $Jan1 = gmmktime(0, 0, 0, 1, 1, $year); $mydate = gmmktime(0, 0, 0, 01, 1, $year); $delta = (int)(($mydate - $Jan1) / (7 * 24 * 60 * 60)) + 1; echo 'weeknumber: ', $delta;
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.38, 7.0.0 - 7.0.33, 7.1.0 - 7.1.25, 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 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
weeknumber: 1

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293.22 ms | 406 KiB | 425 Q