how to know the week of today?

[Brian McCauley]

"C&J" <ggkuo@yahoo.com> writes:

> Is there any way to know what is the current week?

POSIX::strftime supports at least one of the widely used "week number"
algorithms, more on some platforms. (Note that the ISO and POSIX
standards do not agree).

> January 1 is the first week.

That alone does not uniquely define your week number algorithm.

You have to consider when week 2 starts. Does it always start on
January 8 or does it start on the the first Fooday on or after January
2.

Anyhow, whatever your chosen algorithm (within reason) it can be
expressed as a trivial integer expression in terms of $wday and $yday
as retuned by localtime().

If that feels too low-level for you then see Date::* on CPAN.

--
\\ ( )
. _\\__[oo
.__/ \\ /\@
. l___\\
# ll l\\
###LL LL\\

[DOV LEVENGLICK]

$thisday = (Sun,Mon,Tue,Wed,Thu,Fri,Sat)[(localtime)[6]];



C&J wrote:

>Hi,
>Is there any way to know what is the current week?
>January 1 is the first week.
>Thanks
>Chris
>
>
>
>

--
Regards,
Dov Levenglick

[Gunnar Hjalmarsson]

DOV LEVENGLICK wrote:

> C&J wrote:

>>Is there any way to know what is the current week?
>>January 1 is the first week.

>
> $thisday = (Sun,Mon,Tue,Wed,Thu,Fri,Sat)[(localtime)[6]];

Err.. How is that solution related to OP's question?

--
Gunnar Hjalmarsson
Email: [url]http://www.gunnar.cc/cgi-bin/contact.pl[/url]

[Eric Schwartz]

Gunnar Hjalmarsson <noreply@gunnar.cc> writes:

> DOV LEVENGLICK wrote:

>> C&J wrote:

>>>Is there any way to know what is the current week?
>>>January 1 is the first week.

>> $thisday = (Sun,Mon,Tue,Wed,Thu,Fri,Sat)[(localtime)[6]];

>
> Err.. How is that solution related to OP's question?

Not at all, AFAICT, but the solution is in localtime():

$weeknum = int((localtime)[7] / 7);

-=Eric
--
Come to think of it, there are already a million monkeys on a million
typewriters, and Usenet is NOTHING like Shakespeare.
-- Blair Houghton.

[cp]

In article <etor846a9fv.fsf@wormtongue.emschwar>, Eric Schwartz
<emschwar@ldl.fc.hp.com> wrote:

> $weeknum = int((localtime)[7] / 7);

Isn't that inaccurate?
int( 365 / 7 ) = 52

The 365th day of the year ( and on leap years, the 366th also) are in
the 53rd week..

The OP might want to check CPAN for any number of Date manipulation
modules. 'The Perl Cookbook'[1] suggests Date::Calc.

[bash:~]user% perl -e 'use Date::Calc qw(Week_Number);\
print Week_Number('2003', 12, 31), "\n";'

outputs: 53


[1] pp 79 - 80.

--
cp

[JR]

"C&J" <ggkuo@yahoo.com> wrote in message news:<OWlVa.662$Qb7.504188001@newssvr12.news.prodi gy.com>...

> Hi,
> Is there any way to know what is the current week?
> January 1 is the first week.
> Thanks
> Chris

## This may be helpful to you. Good luck. --JR

#!/Perl
use strict;
use warnings;
BEGIN {
eval "use diagnostics";
warn "Can't load diagnostics module.\n\n" if $@;
}

## This assumes a seven day week, and that the first day
## of the year is January 1, xxxx.
printf "This is week %d, of the year %d.", (localtime)[7]/7,
(localtime)[5]+1900;

[Eric Schwartz]

cp <cpryce@pryce.nospam.net> writes:

> In article <etor846a9fv.fsf@wormtongue.emschwar>, Eric Schwartz
> <emschwar@ldl.fc.hp.com> wrote:
>

>> $weeknum = int((localtime)[7] / 7);

>
> Isn't that inaccurate?
> int( 365 / 7 ) = 52

Yeah, sorry:

use POSIX;
$weeknum = ceil((localtime)[7] / 7);

> The 365th day of the year ( and on leap years, the 366th also) are in
> the 53rd week..
>
> The OP might want to check CPAN for any number of Date manipulation
> modules. 'The Perl Cookbook'[1] suggests Date::Calc.

No disrespect intended to either the author of Date::Calc or the
Cookbook, but using Date::Calc for this is rather like swatting a fly
with an M1A1 Abrams. I use modules just about everywhere I can, but
this is such a trivial problem that doesn't particularly need it.
Now, if I wanted to find out what week the next day fell into, I'd
surely use it.

-=Eric
--
Come to think of it, there are already a million monkeys on a million
typewriters, and Usenet is NOTHING like Shakespeare.
-- Blair Houghton.

[C&J]

Hi, all
Thanks all of your help.

"C&J" <ggkuo@yahoo.com> wrote in message
news:OWlVa.662$Qb7.504188001@newssvr12.news.prodig y.com...

> Hi,
> Is there any way to know what is the current week?
> January 1 is the first week.
> Thanks
> Chris
>
>

[Abigail]

cp (cpryce@pryce.nospam.net) wrote on MMMDCXXI September MCMXCIII in
<URL:news:310720031317510686%cpryce@pryce.nospam.n et>:
{} In article <etor846a9fv.fsf@wormtongue.emschwar>, Eric Schwartz
{} <emschwar@ldl.fc.hp.com> wrote:
{}
{} > $weeknum = int((localtime)[7] / 7);
{}
{} Isn't that inaccurate?
{} int( 365 / 7 ) = 52
{}
{} The 365th day of the year ( and on leap years, the 366th also) are in
{} the 53rd week..
{}
{} The OP might want to check CPAN for any number of Date manipulation
{} modules. 'The Perl Cookbook'[1] suggests Date::Calc.
{}
{} [bash:~]user% perl -e 'use Date::Calc qw(Week_Number);\
{} print Week_Number('2003', 12, 31), "\n";'
{}
{} outputs: 53


The methods aren't equivalent, even when you change 'int' to 'ceil'.

Take for instance Jan 6, 2003.

ceil (6 / 7) == 1.

but

Week_Number (2003, 1, 6) == 2.


The latter corresponds with the ISO standard on weeks: weeks start on
Mondays, and week 1 is the week with the first Thursday of the year in
it. This could mean some days of January are in week 52 or 53, and
some days of December could be in week 1.

The former method isn't any standard I know off - it would mean that
weeks start on different days in different years.

Americans, as usual, don't follow international standards. Week 1 in
the US is the week January 1 falls in. Which may, or may not be the
same as the POSIX standard, depending on the year.


Abigail
--
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