1. Find the day of the week of the first day of the month (using Date::Calc, DateTime, localtime or whatever).

  2. Find the number of days to add or subtract.

    Days to first Monday: 

    $days_to_first_monday = ($dow + 7 - 1) % 7;

    [download]

    Days to previous Friday: 

    $days_to_last_friday = ($dow + 7 - 5) % 7 - 7;

    [download]

    In both case, $dow is expected to hold 1..7 for Mon..Sun or 0..6 for Sun..Sat

  3. Use Date::Calc or DateTime to perform the math.

In reply to Re: Calc last friday of month by ikegami
in thread Calc last friday of month by csarid

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