PERL Miscellaneous - multi-line regular expression help

Author

multi-line regular expression help

Cesar Baquerizo

2006-03-31, 6:59 pm

Hello,

I am having a problem trying to match both of the following strings:

03/23 THU 07:09A (b12:00P b12:30P) 04:30P 8:00 0:00 0:00

as well as (embedded newline):

03/27 MON 07:59A [ 11:59A 12:44P] (b12:45P
b01:15P) 04:30P 8:00 0:00 0:00

The first string always matches, but the second never matches. I've
tried different incarnations of the following regex with no success:

(/^\s*\d\d\/\d\d\s+[A-Z][A-Z][A-Z]\s+.*\d\:\d\d\s+\d\:\d\d\s*$/ms)
^^

I was hoping that the above part (.*) would match a newline or anything
else in this case and return it in $&.

Any help appreciated.

Thanks

Paul Lalli

2006-03-31, 6:59 pm

Cesar Baquerizo wrote:
> Hello,
>
> I am having a problem trying to match both of the following strings:
>
> 03/23 THU 07:09A (b12:00P b12:30P) 04:30P 8:00 0:00 0:00
>
> as well as (embedded newline):
>
> 03/27 MON 07:59A [ 11:59A 12:44P] (b12:45P
> b01:15P) 04:30P 8:00 0:00 0:00
>
> The first string always matches, but the second never matches. I've
> tried different incarnations of the following regex with no success:
>
> (/^\s*\d\d\/\d\d\s+[A-Z][A-Z][A-Z]\s+.*\d\:\d\d\s+\d\:\d\d\s*$/ms)
> ^^

Odd, they both match just fine for me:

#!/usr/bin/perl
use strict;
use warnings;

#any newline in string below is the result of newsreader-wrapping
$_ = '03/23 THU 07:09A (b12:00P b12:30P) 04:30P 8:00 0:00
0:00';

if (/^\s*\d\d\/\d\d\s+[A-Z][A-Z][A-Z]\s+.*\d\:\d\d\s+\d\:\d\d\s*$/ms) {

print "First matched\n";
}

#newline in below string after '12:45P'
$_ = '03/27 MON 07:59A [ 11:59A 12:44P] (b12:45P
b01:15P) 04:30P 8:00 0:00 0:00';

if (/^\s*\d\d\/\d\d\s+[A-Z][A-Z][A-Z]\s+.*\d\:\d\d\s+\d\:\d\d\s*$/ms) {

print "Second matched\n";
}
__END__
First matched
Second matched

Perhaps you could post a short-but-complete script (as recommended by
the Posting Guidelines - have you read them yet?) which demonstrates
your error?

Paul Lalli

Tome

2006-03-31, 6:59 pm

I copied and pasted your regex as well as your string and it worked with no problem:

$string = "03/27 MON 07:59A [ 11:59A 12:44P] (b12:45P
b01:15P) 04:30P 8:00 0:00 0:00";
print "$&\n" if $string =~ /^\s*\d\d\/\d\d\s+[A-Z][A-Z][A-Z]\s+.*\d\:\d\d\s+\d\:\d\d\s*$/ms;

It definitely succeeded in the match and printed it fine. .* will match newlines as long as you
have /s.

Maybe if you post your code we can find the problem.

---Tome

On Fri, 31 Mar 2006 16:46:43 GMT, Cesar Baquerizo <ces@cescom.com> wrote:

>Hello,
>
>I am having a problem trying to match both of the following strings:
>
>03/23 THU 07:09A (b12:00P b12:30P) 04:30P 8:00 0:00 0:00
>
>as well as (embedded newline):
>
>03/27 MON 07:59A [ 11:59A 12:44P] (b12:45P
> b01:15P) 04:30P 8:00 0:00 0:00
>
>The first string always matches, but the second never matches. I've
>tried different incarnations of the following regex with no success:
>
>(/^\s*\d\d\/\d\d\s+[A-Z][A-Z][A-Z]\s+.*\d\:\d\d\s+\d\:\d\d\s*$/ms)
> ^^
>
>I was hoping that the above part (.*) would match a newline or anything
>else in this case and return it in $&.
>
>Any help appreciated.
>
>Thanks

Cesar Baquerizo

2006-03-31, 6:59 pm

Actually looking at both your answers made it clear what my problem was.
I incorrectly assumed that multi-line match had an effect on the
contents of $_.

As my data is on multiple lines and I was only reading in 1 line at a
time, I could never match the regex over multiple lines.

Thanks

Tome wrote:[color=darkred]
> I copied and pasted your regex as well as your string and it worked with no problem:
>
> $string = "03/27 MON 07:59A [ 11:59A 12:44P] (b12:45P
> b01:15P) 04:30P 8:00 0:00 0:00";
> print "$&\n" if $string =~ /^\s*\d\d\/\d\d\s+[A-Z][A-Z][A-Z]\s+.*\d\:\d\d\s+\d\:\d\d\s*$/ms;
>
> It definitely succeeded in the match and printed it fine. .* will match newlines as long as you
> have /s.
>
> Maybe if you post your code we can find the problem.
>
> ---Tome
>
> On Fri, 31 Mar 2006 16:46:43 GMT, Cesar Baquerizo <ces@cescom.com> wrote:
>

Tad McClellan

2006-03-31, 6:59 pm

Cesar Baquerizo <ces@cescom.com> wrote:

> I am having a problem trying to match

I'll bet that you are having a problem...

> both of the following strings:
>
> 03/23 THU 07:09A (b12:00P b12:30P) 04:30P 8:00 0:00 0:00
>
> as well as (embedded newline):
>
> 03/27 MON 07:59A [ 11:59A 12:44P] (b12:45P
> b01:15P) 04:30P 8:00 0:00 0:00

.... getting both lines into the string that you are matching against.

Just like in the Frequently Asked Question:

perldoc -q line

I'm having trouble matching over more than one line. What's wrong?

> The first string always matches, but the second never matches.

Are you *certain* that the 2nd string contains what you think
it contains?

Did you print it out to see?

> I've
> tried different incarnations of the following regex with no success:
>
> (/^\s*\d\d\/\d\d\s+[A-Z][A-Z][A-Z]\s+.*\d\:\d\d\s+\d\:\d\d\s*$/ms)

It works for me...

---------------
#!/usr/bin/perl
use warnings;
use strict;

$_ = '03/27 MON 07:59A [ 11:59A 12:44P] (b12:45P
b01:15P) 04:30P 8:00 0:00 0:00';

if (/^\s*\d\d\/\d\d\s+[A-Z][A-Z][A-Z]\s+.*\d\:\d\d\s+\d\:\d\d\s*$/ms)
{ print "it matched\n" }
---------------

--
Tad McClellan SGML consulting
tadmc@augustmail.com Perl programming
Fort Worth, Texas

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