Re: How to find first day of the first week on the month?

"i need to find the first day of the first week of a month."

Firstly, that seems an odd way to ask this. I'm assuming, for a given year and month, you want to know what day (e.g. Sunday) the 1st of that month is. If that's not what you meant, please clarify.

There's a plethora of modules on CPAN that can do this type of thing; however, the builtin module, Time::Piece, can also do this and you already have it installed. So, unless you're already using some Date::*, Time::*, etc. module, Time::Piece is probably your best choice. Here's sample code:

#!/usr/bin/env perl -l

use strict;
use warnings;

use Time::Piece;

# In 2 days it will be Tuesday, 1st October 2013
my $month = 10;
my $year = 2013;
my $day_name = Time::Piece->strptime("$year$month" . '01', '%Y%m%d')->
+fullday;

print "01-Oct-2013 is a $day_name";
[download]

Output:

01-Oct-2013 is a Tuesday
[download]

-- Ken

Comment on Re: How to find first day of the first week on the month? Select or Download Code

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Re^2: How to find first day of the first week on the month? by BillKSmith (Monsignor) on Sep 29, 2013 at 00:10 UTC
It sure is an odd question. I thought he meant "What is the date of the first Sunday (or perhaps Monday) of the month?" Bill	[reply]
Re^3: How to find first day of the first week on the month? by kcott (Archbishop) on Sep 29, 2013 at 07:01 UTC
You could be right. We'll have to wait for devbond to tell us. Anyway, that's just as easy to calculate: `#!/usr/bin/env perl -l use strict; use warnings; use Time::Piece; my $month = 10; my $year = 2013; for (1 .. 7) { # Time::Piece->wday returns: Sunday = 1, ..., Saturday += 7 print +($_ - Time::Piece->strptime("$year$month" . '01', '%Y%m%d') +->wday) % 7 + 1; }` [download] Output: `6 7 1 2 3 4 5` [download] Check: `$ cal 10 2013 October 2013 Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31` [download] -- Ken	[reply] [d/l] [select]
Re^2: How to find first day of the first week on the month? ( strptime %Y-%j time-piece-firstlastofeverymonth.pl) by Anonymous Monk on Sep 28, 2013 at 23:42 UTC
Doing day math with %j which is day of year (yday) #!/usr/bin/perl -- ## perltidy -olq -csc -csci=10 -cscl="sub : BEGIN END" -otr -opr -ce +-nibc -i=4 -pt=0 "-nsak=*" use strict; use warnings; use Time::Piece; my $now = localtime; my $year = shift \|\| $now->year; for my $mon ( 1 .. 12 ) { my $first = Time::Piece->strptime( qq/$year-$mon/, q/%Y-%m/ ); my $mon = $first->mon; my $yday = $first->yday; my( $last ) = grep { $_->mon == $mon } map { Time::Piece->strptime( qq/$year-$_/, q/%Y-%j/ ) } map { $yday + $_ } reverse 28 .. 31; printf '%4d %3s %02d/%02d-%02d/%02d ', $first->year, $first->month, $first->mon, $first->mday, $last->mon, $last->mday,; print "\n" if 0 == $mon % 3; } __END__ 2013 Jan 01/01-01/31 2013 Feb 02/01-02/28 2013 Mar 03/01-03/31 2013 Apr 04/01-04/30 2013 May 05/01-05/31 2013 Jun 06/01-06/30 2013 Jul 07/01-07/31 2013 Aug 08/01-08/31 2013 Sep 09/01-09/30 2013 Oct 10/01-10/31 2013 Nov 11/01-11/30 2013 Dec 12/01-12/31 [download]	[reply] [d/l]