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checking for a valid date-time
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Dan and Shell
#1 / 5
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 checking for a valid date-time Does anyone know a better way than this:
start:
$a = <STDIN>;
chomp($a);
if ("$a" =~ /(\d{2})(\d{2})(\d{2})/) {
$days = $1;
$hours = $2;
$minutes = $3;
Quote: } else { print "$a isn't valid.\n" }
if ($days < 32 && $hours < 24 && $minutes < 60) {
print "$a is valid\n";
Quote: } else { print "$a isn't valid\n" }
goto start
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| Wed, 18 Jun 1902 08:00:00 GMT |
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Gwyn Ju
#2 / 5
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checking for a valid date-time
say such a terrible thing:
Quote: >Does anyone know a better way than this: >start:
>$a = <STDIN>;
>chomp($a);
>if ("$a" =~ /(\d{2})(\d{2})(\d{2})/) {
> $days = $1;
> $hours = $2;
> $minutes = $3;
>} else { print "$a isn't valid.\n" }
>if ($days < 32 && $hours < 24 && $minutes < 60) {
> print "$a is valid\n";
>} else { print "$a isn't valid\n" }
>goto start
need to stringify $a in the match and for that matter you could use a
better variable name than $a (which is special anyway, see perdoc -f
sort) like $input or something but what I think you want to know is:
perldoc Time::ParseDate
perldoc -f localtime
--
:self-reference: n. See {self-reference}.
From "The New Hackers Dictionary", version 4.2
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| Sat, 15 Mar 2003 09:47:41 GMT |
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Martien Verbrugg
#3 / 5
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checking for a valid date-time On Mon, 25 Sep 2000 23:21:26 +0900,
Quote: > Does anyone know a better way than this: > start:
> $a = <STDIN>;
> chomp($a);
> if ("$a" =~ /(\d{2})(\d{2})(\d{2})/) {
> $days = $1;
> $hours = $2;
> $minutes = $3;
> } else { print "$a isn't valid.\n" }
> if ($days < 32 && $hours < 24 && $minutes < 60) {
> print "$a is valid\n";
> } else { print "$a isn't valid\n" }
> goto start
use strict;
while (<STDIN>)
{
chomp;
my ($day, $hour, $minute) = /^(\d\d)(\d\d)(\d\d)$/;
print "$_ is ",
!$minute || $day > 31 || $hour > 24 || $minute > 60 ? 'not ' : '',
"valid\n";
Quote: }
Note however, that this is slightly different from yours. Yours
matches the first six digits in a string, mine insists that the only
strings allowed have to have six digits and no more. Also note that
the check on '$day' is slightly weak, because for example, February
doesn't have 31 days. Without knowing anythjng about the month
however, you can't make it more specific.
Notes: mainly on style: Do use -w and the strict pragma. They'll help
you debug programs better. Don't use $a or $b unless you are in a sort
subroutine. They're special. Don't use gotos unless you are prepared
to justify it, and can come up with a damned good reason. Properly
indent your code; it's just too hard to read this way.
Martien
--
Martien Verbruggen |
Interactive Media Division | Unix is user friendly. It's just
Commercial Dynamics Pty. Ltd. | selective about its friends.
NSW, Australia |
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| Sat, 15 Mar 2003 11:40:40 GMT |
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Clay Irvi
#4 / 5
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checking for a valid date-time On Mon, 25 Sep 2000 23:21:26 +0900, Dan and Shelly
Quote:
>Does anyone know a better way than this: >start:
>$a = <STDIN>;
>chomp($a);
>if ("$a" =~ /(\d{2})(\d{2})(\d{2})/) {
> $days = $1;
> $hours = $2;
> $minutes = $3;
>} else { print "$a isn't valid.\n" }
>if ($days < 32 && $hours < 24 && $minutes < 60) {
> print "$a is valid\n";
>} else { print "$a isn't valid\n" }
>goto start
Perl modules are your friend.
#!/usr/local/bin/perl -w
use Time::ParseDate;
while ($time = <DATA>) {
chomp $time;
$epoch_seconds = parsedate("$time", VALIDATE => 1);
if (! $epoch_seconds) {
print "$time is invalid\n";
}
}
__DATA__
12:00:00
01:52:45
25:15:00
04:61:00
15:05:64
prints:
25:15:00 is invalid
04:61:00 is invalid
15:05:64 is invalid
--
Ah, but a man's reach should exceed his grasp
- or what's a heaven for? -- Robert Browning
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| Wed, 18 Jun 1902 08:00:00 GMT |
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Martien Verbrugg
#5 / 5
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checking for a valid date-time On 26 Sep 2000 12:08:35 GMT,
Quote: > On Mon, 25 Sep 2000 23:21:26 +0900, Dan and Shelly
> >Does anyone know a better way than this:
> >start:
> >$a = <STDIN>;
> >chomp($a);
> >if ("$a" =~ /(\d{2})(\d{2})(\d{2})/) {
> > $days = $1;
> > $hours = $2;
> > $minutes = $3;
Quote: > Perl modules are your friend. > #!/usr/local/bin/perl -w
> use Time::ParseDate;
> while ($time = <DATA>) {
> chomp $time;
> $epoch_seconds = parsedate("$time", VALIDATE => 1);
> if (! $epoch_seconds) {
> print "$time is invalid\n";
> }
> }
> __DATA__
> 12:00:00
> 01:52:45
> 25:15:00
> 04:61:00
> 15:05:64
the input is a concatenation of three two-digit numbers, the first of
which specifies a day, the second an hour, and the third a minute.
Without munging that before giving it to parsedate, I doubt very much
that you'll be able to make it validate. Besides that, without
providing the context of a month and year,it would be impossible for
anything to do that correctly.
If it was only a time, ok. If it was only a date, ok as well. But
given the input, the only validation that is possible is a broad one.
Now.. it might very well be possible that the OP could get their data
in a more decent format, but that's an entirely different issue.
Martien
--
Martien Verbruggen |
Interactive Media Division | Useful Statistic: 75% of the people
Commercial Dynamics Pty. Ltd. | make up 3/4 of the population.
NSW, Australia |
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| Sun, 16 Mar 2003 09:24:53 GMT |
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