Seeking the

Rpick has asked for the wisdom of the Perl Monks concerning the following question:

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Formatting Dates by gellyfish (Monsignor) on Feb 06, 2002 at 22:01 UTC
`sprintf` is the baby that you want to use - you will be able to read about that more in the documentation. But as date things are a very common use I'll repeat an example: `use strict; use warnings; my ( $day, $month, $year ) = (localtime)[3,4,5]; my $date = sprintf "%.04d%.02d%.02d", $year + 1900, $month + 1, $day;` [download] I'm sure this code has been shown thousands of time before /J\	[reply] [d/l] [select]
Re: Seeking the by Bepa (Beadle) on Feb 06, 2002 at 21:46 UTC
You will want to use `sprintf()` to make sure the month is always two digits. This is Bepa	[reply] [d/l]
Re: Seeking the by rjray (Chaplain) on Feb 06, 2002 at 22:44 UTC
Based on your updated reply saying that you aren't planning on printing them, I can only assume you are using them for string comparisons. Otherwise, the presence of the leading zero would be meaningless in a numeric comparison. (And no, it wouldn't cause evaluation as octal.) Also, like one other person showed, it would be much more efficient to get `$month` and increment it, rather than subscripting a constant array as you are in your sample code. Getting back to your question, there are two ways to produce the strings you want: `($day, $month, $year) = (localtime)[3 .. 5]; $year += 1900; # Method 1: $day = sprintf "%02d", $day; $month = sprintf "%02d", $month + 1; # Method 2: $day = substr("0$day", -2); $month++; $month = substr("0$month", -2);` [download] As you can see, `printf` is still you best tool here, though strictly-speaking you are using its cousin `sprintf`. --rjray	[reply] [d/l]
Re: Seeking the by Spudnuts (Pilgrim) on Feb 06, 2002 at 23:39 UTC
I prefer to use the POSIX function `strftime`. An example of this would be: `use strict; use warnings; use POSIX qw(strftime); print strftime("%Y%m%d", localtime()), "\n";` [download] Here are descriptions of the format flags. The man page is from FreeBSD, but most of the flags are standards-compliant, so it's pretty much a moot point. I find this preferable because it requires significantly fewer lines of code and reuses library functionality.	[reply] [d/l] [select]
Re: Seeking the by data64 (Chaplain) on Feb 07, 2002 at 01:54 UTC
If converting to string is all the date manipulation you are doing, then sprintf is probably good enough. If you are doing more involved computation, look at Date::Business.	[reply]
Re: Seeking the by Parham (Friar) on Feb 07, 2002 at 00:37 UTC
Just a bit off topic... Correctly speaking, sprintf() and printf() are probably the better solution. But it seems that you're unfamiliar with those and more comfortable concatinating leading zeros. There is absolutely nothing wrong with the way your doing things, there is always more than one way to do things and your way seems just as good as any other. to answer your question though: `$day = 5; #test variable $month = 7; #test variable $day = sprintf("%02d",$day); $month = sprintf("%02d",$month); print "$day\n$month";` [download] would print: 05 07	[reply] [d/l]
Re: Seeking the by Rpick (Novice) on Feb 06, 2002 at 22:25 UTC
OOPS, My code's not a good example. I was using it to see what happened to the values of the variables, and I think the wrong impression was given. These values probably will not be printed. If I can get this to work they will be used for a comparison. Probably something I should be using a regular expression for, but I'm just getting started and regexs are still a bit incomprehensible. I need the leading 0 on the month and day if they are less than 9 and the value will not be printed, so although I thank you for your answers I don't think sprintf will work.	[reply]
Re: Re: Seeking the by gellyfish (Monsignor) on Feb 06, 2002 at 22:30 UTC
No, `sprintf` is exactly what you want - it formats into a string without printing Please refer to the `perlfunc` manpage for more details. /J\	[reply] [d/l] [select]