Re: RE: figuring out the number of sundays in a given year
Jerry Wilcox [EMAIL PROTECTED] wrote: I'm not sure about the count in a year, but I frequently need to determine how many of a given day of the week fall in a given month of the year, or, more precisely, given that today is Saturday, September 20, I need to figure out whether today is the first, second, third, fourth, or fifth Saturday of the month. I've worked out code using existing methods to tell me what I need to know, and I'm not sure that an entirely new method is warranted here. Jerry: There's two functionality in the above. First: How many of a particular DOW are in a period. This is just a matter of dividing the total days by seven then adding one if needed. If a function were added for this, then I imagine its more a part of DateTime::Span rather than DateTime itself. Secondly you ask about getting the weekday of the month. There's already a function in DateTime for this: $dt-weekday_of_month(); Test it with this: perl -MDateTime -e 'print DateTime-new( year = 2003, month = 9, day = 20)-weekday_of_month()'
Re: RE: figuring out the number of sundays in a given year
First: How many of a particular DOW are in a period. This is just a matter of dividing the total days by seven then adding one if needed. If a function were added for this, then I imagine its more a part of DateTime::Span rather than DateTime itself. I already said this. :) Secondly you ask about getting the weekday of the month. There's already a function in DateTime for this: $dt-weekday_of_month(); Yes - but if we add the above functionality to DT::Span I think we should also have weekday_of_span() or a similar method for finding your location relativity to the start of the span (and not just the current month). -J --
RE: figuring out the number of sundays in a given year
At 11:40 PM -0500 9/19/03, Dave Rolsky wrote: DateTime-day_count_in_year( year = 1999, day = 4 ); I think this is what was originally meant. What would people need this info for? I'm not sure about the count in a year, but I frequently need to determine how many of a given day of the week fall in a given month of the year, or, more precisely, given that today is Saturday, September 20, I need to figure out whether today is the first, second, third, fourth, or fifth Saturday of the month. I've worked out code using existing methods to tell me what I need to know, and I'm not sure that an entirely new method is warranted here. Jerry -- Jerry Wilcox - University of California, Office of the President Manager Payroll/Personnel Services -- Information Resources Communications 415 20th Street (3rd Floor) Oakland, CA 94612 -- 510-987-0516 -- FAX 510-763-5597 ``The lyf so short, the craft so long to lerne.'' - Chaucer
RE: figuring out the number of sundays in a given year
I'm not sure about the count in a year, but I frequently need to determine how many of a given day of the week fall in a given month of the year, or, more precisely, given that today is Saturday, September 20, I need to figure out whether today is the first, second, third, fourth, or fifth Saturday of the month. I've worked out code using existing methods to tell me what I need to know, and I'm not sure that an entirely new method is warranted here. To generalize: You want to know how many of a given day occur in a range and at what position in that range a given datetime is? This sounds like something that should operate on a DT::Span object. -J --
RE: figuring out the number of sundays in a given year
On 9/20/03 Joshua Hoblitt wrote: I'm not sure about the count in a year, but I frequently need to determine how many of a given day of the week fall in a given month of the year, or, more precisely, given that today is Saturday, September 20, I need to figure out whether today is the first, second, third, fourth, or fifth Saturday of the month. I've worked out code using existing methods to tell me what I need to know, and I'm not sure that an entirely new method is warranted here. To generalize: You want to know how many of a given day occur in a range and at what position in that range a given datetime is? This sounds like something that should operate on a DT::Span object. It's a recurrence set. -count is how many, index in set array (+1) is position. - Bruce __bruce__van_allen__santa_cruz__ca__
Re: figuring out the number of sundays in a given year
Hi Dave Josh, Dave Rolsky [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] On Wed, 17 Sep 2003, Hill, Ronald wrote: [snipped] Josh is confused because you're passing arguments to the day_of_week method. These arguments are completely ignored by DateTime.pm! -dave Ok, I see I can just do my $dow = $dt2-day_of_week( year = $dt-year, ); and get what I want, which is the dow for jan 1 Hmn!! But the questions is should I code like that. Doing something like this does not seem very intuitive. Ron
Re: figuring out the number of sundays in a given year
Syamala Tadigadapa wrote: Here is a simple solution ... I'd hate to see your complex solution ... Rick
Re: figuring out the number of sundays in a given year
On Wed, 17 Sep 2003, Ron Hill wrote: Ok, I see I can just do my $dow = $dt2-day_of_week( year = $dt-year, ); The day_of_week() method DOES NOT TAKE ARGUMENTS! I don't know what you think the code above does, but I can tell you that all it does is return the day of the week for the $dt2 objcet, and ignores everything else. -dave /*=== House Absolute Consulting www.houseabsolute.com ===*/
Re: figuring out the number of sundays in a given year
The day_of_week() method DOES NOT TAKE ARGUMENTS! I wonder if it's worth the overhead of checking for extraneous parameters on all methods? -J --
Re: figuring out the number of sundays in a given year
On Fri, 19 Sep 2003, Joshua Hoblitt wrote: The day_of_week() method DOES NOT TAKE ARGUMENTS! I wonder if it's worth the overhead of checking for extraneous parameters on all methods? I'd rather try to keep accessors as quick as possible. -dave /*=== House Absolute Consulting www.houseabsolute.com ===*/
Re: figuring out the number of sundays in a given year
Hi Ron,
I'm a bit confused by your parameters to day_of_week().
This is the actual implementation from DateTime.pm
sub day_of_week { $_[0]-{local_c}{day_of_week} }
-J
--
script=
use strict;
use warnings;
use DateTime;
my $dt = DateTime-new( year = 2001 );
my $num = number_of_sundays($dt);
print $num;
sub number_of_sundays {
my ($dt) = @_;
my $dt2 = $dt-clone();
if ( $dt-is_leap_year ) {
my $dow = $dt2-day_of_week(
year = $dt-year,
month = 1,
day = 1,
);
return 53 if ( $dow == 7 or $dow == 6 );
}
else {
my $dow = $dt2-day_of_week(
year = $dt-year,
month = 1,
day = 1,
);
return 53 if ( $dow == 7 );
}
return 52;
}
RE: figuring out the number of sundays in a given year
Hi Josh,
Hi Ron,
I'm a bit confused by your parameters to day_of_week().
This is the actual implementation from DateTime.pm
sub day_of_week { $_[0]-{local_c}{day_of_week} }
-J
I compute the number of days in the current year
I figure out the day of week for january the first
and if this is (365 days in the year and Sunday or 7 in datetime) or
(Saturday
6 in datetime or Sun and a leap year) then I return 53 sundays as the
number of sundays
else I return 52 as the number of sundays.
I checked the docs for datetime and used them
F:\scriptsperldoc DateTime|grep day_of_week
File STDIN:
$dow= $dt-day_of_week; # 1-7 (Monday is 1) - also dow, wday
_0. So for example, this class provides both day_of_week() and
day_of_week_0() methods.
The day_of_week_0() method still treats Monday as the first day of the
* day_of_week, wday, dow
Am I missing something?
Thanks
Ron Hill
RE: figuring out the number of sundays in a given year
On Wed, 17 Sep 2003, Hill, Ronald wrote: I checked the docs for datetime and used them F:\scriptsperldoc DateTime|grep day_of_week File STDIN: $dow= $dt-day_of_week; # 1-7 (Monday is 1) - also dow, wday _0. So for example, this class provides both day_of_week() and day_of_week_0() methods. treats Monday as the first day of the * day_of_week, wday, dow Am I missing something? Josh is confused because you're passing arguments to the day_of_week method. These arguments are completely ignored by DateTime.pm! -dave /*=== House Absolute Consulting www.houseabsolute.com ===*/
Re: figuring out the number of sundays in a given year
Here is a simple solution (unless you are bent on doing it in a longer way
using a date time class.)
sub jan1{
my $y = shift;
my $m = 1; $d = 1;
$m = 11; $y--;
my $c = int($y / 100); $yy = $y %100;
my $z = ( 1 + $yy + int($yy/4) + int($c/4) - 2*$c) % 7;
$z += 7 if $z 0;
return $z; # 0 == Sun day. 6 == Sat. day.
}
sub sundays{
my $year = shift;
my $j1st = jan1($year);
return 53 if $j1st == 0 || ($j1st == 6 jan1($year+1) == 1);
return 52;
}
_
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