splitting a string into arbitrary lengths

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

Replies are listed 'Best First'.
Re: splitting a string into arbitrary lengths by rev_1318 (Chaplain) on Jun 22, 2005 at 21:36 UTC
Try unpack: `($tyear, $tmon, $tday) = unpack("a4a2a2", $today);` [download] Paul	[reply] [d/l]
Re^2: splitting a string into arbitrary lengths by ryanc (Monk) on Jun 22, 2005 at 21:41 UTC
ahh, very nice...thanks!	[reply]
Re^3: splitting a string into arbitrary lengths by demerphq (Chancellor) on Jun 22, 2005 at 22:33 UTC
(un)pack will likely be the fastest way to do this. Don't forget you can put spaces in appropriate places in the pattern to make it easier to read. (I say 'pack' because the useful documentation for 'unpack' is in 'pack'. :-) --- $world=~s/war/peace/g	[reply]
Re: splitting a string into arbitrary lengths by kirbyk (Friar) on Jun 22, 2005 at 21:34 UTC
You could do it with a regex as well: `my ($tyear, $tmon, $tday) = ($today =~ /(\d{4})(\d{2})(\d{2})/);` [download] This would be a good route if you had a less standard format, like optional dashes. -- Kirby, WhitePages.com	[reply] [d/l]
Re^2: splitting a string into arbitrary lengths by ihb (Deacon) on Jun 23, 2005 at 20:49 UTC
That is what I'd perhaps use too, depending on the application. If I'd chose this way I'd even tag along a success check (and add anchors). Your format may change some day and then you'll be glad you caught that. `my ($y, $m, $d) = $today =~ /^(\d\d\d\d)(\d\d)(\d\d)\z/ or die "Incorrect date format: '$today'";` [download] `ihb` See perltoc if you don't know which perldoc to read!	[reply] [d/l]
Re: splitting a string into arbitrary lengths by bmann (Priest) on Jun 22, 2005 at 21:40 UTC
unpack `my ($tyear, $tmon, $tday) = unpack( 'A4A2A2', '20050622' );` If you choose to use this, you might also want to read pack and perlpacktut	[reply] [d/l]
Re: splitting a string into arbitrary lengths by moot (Chaplain) on Jun 22, 2005 at 21:32 UTC
How's about: `my ($y, $m, $d) = $today =~ /(\d){4}(\d){2}(\d){2}/;` [download] ..although as a previous poster mentioned, you might lose a little in readability. Now hiring in Atlanta. /msg moot for details.	[reply] [d/l]
Re^2: splitting a string into arbitrary lengths by bmann (Priest) on Jun 22, 2005 at 22:03 UTC
`my ($y, $m, $d) = $today =~ /(\d){4}(\d){2}(\d){2}/;` ..although as a previous poster mentioned, you might lose a little in readability. You will want to move the closing parens to after the quantifiers for each group of digits, or you'll lose more than just readability ;) As written, the regex will only capture the last digit in each group. `my $today = 20050622; my ($y, $m, $d) = $today =~ /(\d){4}(\d){2}(\d){2}/; print join ":", $y, $m, $d; # prints 5:6:2, not 2005:06:22` [download]	[reply] [d/l] [select]
Re^3: splitting a string into arbitrary lengths by moot (Chaplain) on Jun 23, 2005 at 02:20 UTC
crap, you're right. good catch. -- Now hiring in Atlanta. /msg moot for details.	[reply]
Use a date module :) by mugwumpjism (Hermit) on Jun 23, 2005 at 00:36 UTC
If you're splitting a date into its components, why not use a Date module? `use Time::Piece; my $time = Time::Piece->strptime("20050622", "%Y%m%d"); my ($tyear, $tmon, $tday) = ($time->year, $time->mon, $time->mday)` [download] Ok, it's not quite as small as a straight regex match, but quite often when you are playing with dates manually like this, it pays to use a module like Time::Piece, DateTime or even Date::Manip. The advantages now don't seem worth it - but as you start to work with dates more, you'll appreciate having objects for them so you can do calculations on them without missing things. $h=$ENV{HOME};my@q=split/\n\n/,`cat $h/.quotes`;$s="$h/." ."signature";$t=`cat $s`;print$t,"\n",$q[rand($#q)],"\n"; [download]	[reply] [d/l] [select]
Re: splitting a string into arbitrary lengths by BazB (Priest) on Jun 22, 2005 at 21:25 UTC
There's nothing wrong with what you're doing; anything else is likely to simply be obfuscation. If the information in this post is inaccurate, or just plain wrong, don't just downvote - please post explaining what's wrong. That way everyone learns.	[reply]
Re^2: splitting a string into arbitrary lengths by ryanc (Monk) on Jun 22, 2005 at 21:32 UTC
obfuscated code welcomed.	[reply]
Re: splitting a string into arbitrary lengths by ank (Scribe) on Jun 23, 2005 at 00:35 UTC
How about a regexp, but using the `/x` modifier: `my ($tyear, $tmon, $tday) = ($today =~ /^(\d{4}) # 4 digit year (\d{2}) # 2 digit month (\d{2})$/x); # 2 digit day` [download] -- ank	[reply] [d/l] [select]
Re: splitting a string into arbitrary lengths by planetscape (Chancellor) on Jun 23, 2005 at 17:47 UTC
If your problem definition really is as simple as your title, check out Puzzlement in Splitsville. However, I really think mugwumpjism has it nailed: Use a date module :). Good luck, planetscape	[reply]
Re^2: splitting a string into arbitrary lengths by ryanc (Monk) on Jun 23, 2005 at 20:16 UTC
I actually was doing this at first but the program I'm writing has to be as portable as possible, so I'm trying to avoid the inclusion of all but the absolute necessary modules. thanks. ryanc	[reply]


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