datetimestamp faster/golf/prettier

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

Esteemed Monks, My database wants me to generate a datetime in this format:
YYYYMMDDHHMMSS
Perl's localtime() function has annoyed me since the begining of time but i still use it to solve this problem. Anyone can think of a better/faster/prettier/shorter(golf) solution (not using DateTime etc.)?

#!/usr/bin/perl -w

use strict;
use Benchmark;
use POSIX;

Benchmark::cmpthese(100000, {
'Reference Implementation' => '
        my @time = localtime();
        my $time = sprintf("%04d%02d%02d%02d%02d%02d", $time[5] + 1900
+, $time[4] + 1, $time[3], $time[2], $time[1], $time[0]);
',
'Reverse Array' => '
        my @time = localtime();
        my $time = sprintf("%04d%02d%02d%02d%02d%02d", $time[5] + 1900
+, $time[4] + 1, reverse(@time[0 .. 3]));
',
'Shorter Array' => '
        my @time = (localtime())[0 .. 5];
        my $time = sprintf("%04d%02d%02d%02d%02d%02d", $time[5] + 1900
+, $time[4] + 1, $time[3], $time[2], $time[1], $time[0]);
',
'strftime by Joost' => '
        my $time = strftime("%Y%m%d%H%S",localtime);
'
});
[download]

Comment on datetimestamp faster/golf/prettier Download Code

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Re: datetimestamp faster/golf/prettier by Joost (Canon) on Jul 20, 2004 at 14:50 UTC
`perl -MPOSIX=strftime -e'print strftime("%Y%m%d%H%S",localtime)'` update: s/%M/%m/ "What should it profit a man, if he should win a flame war, yet lose his cool?"	[reply] [d/l]
Re: datetimestamp faster/golf/prettier by dragonchild (Archbishop) on Jul 20, 2004 at 14:53 UTC
What database are you using that requires you to do such a ridiculous thing?? Surely there's a function that your database provides that will allow you to either cast a string to the appropriate structure and/or provide the timestamp yourself. For example, MySQL will do timestamping for you with the TIMESTAMP column. You can create a trigger in Oracle that will populate the timestamping column at the right time. Other RDBMS's have similar features. The only one I can think of that might require this is SQLite, but you aren't required to put it in any format for SQLite (as it stores everything as strings, anyway). ------ We are the carpenters and bricklayers of the Information Age. Then there are Damian modules.... sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon.* - flyingmoose I shouldn't have to say this, but any code, unless otherwise stated, is untested	[reply]
Re^2: datetimestamp faster/golf/prettier by Jaap (Curate) on Jul 20, 2004 at 14:55 UTC
I'm using MySQL and i use the column with the timestamp as a (shared) primary key. I tried to insert a NULL and it gave me a nice error.	[reply]
Re^3: datetimestamp faster/golf/prettier by dragonchild (Archbishop) on Jul 20, 2004 at 15:03 UTC
I have a few questions: Which version of MySQL? The handling of TIMESTAMP changes in v4.1.0 and 4.1.2 What error are you seeing? Can you show me the structure of the table and the code used to insert the value? ------ We are the carpenters and bricklayers of the Information Age. Then there are Damian modules.... sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon.* - flyingmoose I shouldn't have to say this, but any code, unless otherwise stated, is untested	[reply]
Re^4: datetimestamp faster/golf/prettier by Jaap (Curate) on Jul 20, 2004 at 15:11 UTC
Re^5: datetimestamp faster/golf/prettier by Joost (Canon) on Jul 20, 2004 at 15:16 UTC
Re: datetimestamp faster/golf/prettier by Jaap (Curate) on Jul 20, 2004 at 14:59 UTC
Benchmark: timing 100000 iterations of Reference Implementation, Rever +se Array, Shorter Array, strftime... Reference Implementation: 1 wallclock secs ( 0.66 usr + 0.03 sys = +0.69 CPU) @ 144927.54/s (n=100000) Reverse Array: 1 wallclock secs ( 0.85 usr + 0.03 sys = 0.88 CPU) @ + 113636.36/s (n=100000) Shorter Array: 0 wallclock secs ( 0.63 usr + 0.04 sys = 0.67 CPU) @ + 149253.73/s (n=100000) strftime: 1 wallclock secs ( 0.52 usr + 0.07 sys = 0.59 CPU) @ 16 +9491.53/s (n=100000) Rate Reverse Array Reference Implementati +on Shorter Array strftime Reverse Array 113636/s -- -2 +2% -24% -33% Reference Implementation 144928/s 28% +-- -3% -14% Shorter Array 149254/s 31% +3% -- -12% strftime 169492/s 49% 1 +7% 14% -- [download]	[reply] [d/l]
Re^2: datetimestamp faster/golf/prettier by dragonchild (Archbishop) on Jul 20, 2004 at 17:20 UTC
I would strongly recommend timing for a given number of seconds, preferably 5 or 10. Look at the POD for Benchmark as to how to do this. ------ We are the carpenters and bricklayers of the Information Age. Then there are Damian modules.... sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon.* - flyingmoose I shouldn't have to say this, but any code, unless otherwise stated, is untested	[reply]