in reply to getting the First day of the month

Your question is a little confusing, you ask how to get the first day of the month and then cut-and-paste Date::Calc instructions on figuring out the first Monday of a week. If you want the first day of the month, simply refer to is with the number '1'. No Data::Calc required, that's always the first day.

Now how to figure the first Monday of a given month? It takes a little logic, what the Date::Calc instructions are explaining is how to get the Monday of any given week, now if you want the first Monday of the month you should check Monday_of_Week() of the first day of a month. If the result is in the same month, you got lucky and Monday falls on the first, if not, increment the week of the year by 1 and you will have your answer. 


#$year, $month, and $day are set to the first of any given month
my ($week,undef)=Week_of_Year($year,$month,$day);
my (undef, $tmpmonth, $firstmonday)=Monday_of_Week($week,$year);
if ($tmpmonth != $month)
{
(undef, undef, $firstmonday)=Monday_of_Week(++$week,$year);
}

#$firstmonday now contains the date of the first Monday of a given mon
+th.
#Put this in a loop or a sub or whatever and you can call it with argu
+ments.
print "First monday of $month/$year is $firstmonday\n";

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Replies are listed 'Best First'.
Re: Re: getting the First day of the month
by Anonymous Monk on Aug 02, 2003 at 23:58 UTC
    Thanks vroom, When I plug this into a loop I am getting these results . I am confused. They are all Mondays but just not always the first Monday. 
    foreach my $item (1..12) {
my $year = 2003;
my $month = $item;
my $day = 12;
my ($week,undef)=Week_of_Year($year,$month,$day);
my (undef, $tmpmonth, $firstmonday)=Monday_of_Week($week,$year);
if ($tmpmonth != $month)
{
(undef, undef, $firstmonday)=Monday_of_Week(++$week,$year);
}

    [download]
    First monday of 1/2003 is 6
    First monday of 2/2003 is 10
    First monday of 3/2003 is 10
    First monday of 4/2003 is 7
    First monday of 5/2003 is 12
    First monday of 6/2003 is 9
    First monday of 7/2003 is 7
    First monday of 8/2003 is 11
    First monday of 9/2003 is 8
    First monday of 10/2003 is 6
    First monday of 11/2003 is 10
    First monday of 12/2003 is 8
[reply]
[d/l]
      I see now. You want a list of 12 dates, each one the first Monday of the month. Personally, i am not a huge fan of Date::Calc, and prefer Time::Piece and DateTime. Here is some code that uses the latter: 
      use strict;
use warnings;
use DateTime;

my $year = DateTime->now->year;
for my $month (1..12) {
   my $dt = DateTime->new(year => $year, month => $month);
   $dt->add(days => 1) until $dt->day_of_week == 1;
   printf "First monday of %02d/%d is %s\n",
      $dt->month, $dt->year, $dt->day,
   ;
}

__END__
First monday of 01/2003 is 6
First monday of 02/2003 is 3
First monday of 03/2003 is 3
First monday of 04/2003 is 7
First monday of 05/2003 is 5
First monday of 06/2003 is 2
First monday of 07/2003 is 7
First monday of 08/2003 is 4
First monday of 09/2003 is 1
First monday of 10/2003 is 6
First monday of 11/2003 is 3
First monday of 12/2003 is 1

      [download]
      (psst ... that was pzbagel you replied to, not vroom ;))

      jeffa

      L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)
[reply]
[d/l]

      Ummm, first off my name is pzbagel, not vroom.

      Secondly, $day should be set to 1 and not 12 as you have set it. That is why you are getting the wrong Monday in your loop. Change $day to 1 and you will be set.

[reply]

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