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Perl regex help.

jaimitoc30
Novice

Apr 10, 2012, 10:31 AM

Post #1 of 6 (1426 views)

Perl regex help.	Can't Post

Hi, I am trying to make a regular expression to detect one of the following:

acti
baja
info
xx.xx xxxxxxxx <--- where x are numbers 0-9, example:
5.00 65436765
10.00 65436765

I was able to match the last one using this regex:

Code

$text =~ /^\s*([0-9]{1,2}[]{0,1}|[0-5]{1,2}[][0,5]{0,1}[0]{0,1})\s+([0-9]{8})\s*$/;

And now, I want to include the first 3 strings in one regex:

Code

text =~ /^\s*([0-9]{1,2}[]{0,1}|[0-5]{1,2}[][0,5]{0,1}[0]{0,1})\s+([0-9]{8})|(acti|baja|info)\s*$/;

but it won't work for none of the examples it should match above.

Can somebody give me some lights here?

Thank you and regards.

BillKSmith
Veteran

Apr 10, 2012, 1:00 PM

Post #2 of 6 (1419 views)

Re: [jaimitoc30] Perl regex help. [In reply to]	Can't Post

I must not understand your problem. I have prepared a complete perl program to demonstrate my understanding of it.

Code

use strict; 
use warnings; 
my @samples = ( 
    'acti',  
    'baja',  
    'info', 
    '5.00 65436765', 
    '10.00 65436765',  
); 
my $regex1 = 
    qr/^\s*([0-9]{1,2}[]{0,1}|[0-5]{1,2}[][0,5]{0,1}[0]{0,1})\s+([0-9]{8})\s*$/; 
my $regex2 = 
    qr/^\s*([0-9]{1,2}[]{0,1}|[0-5]{1,2}[][0,5]{0,1}[0]{0,1})\s+([0-9]{8})| 
       (acti|baja|info)\s*$ 
      /x;  
 
foreach my $text (@samples) { 
    if ($text =~ $regex1) { 
        print "Regex_1 Matched: $text\n"; 
    } 
    if ($text =~ $regex2) { 
        print "Regex_2 Matched: $text\n"; 
    } 
}

You expect $regex1 to match the numeric examples and $regex2 to match all the examples. You claim that $regex1 matches something, but $regex2 does not. This is not at all the case. $regex2 matches the text examples. $regex1 does not match anything.

Please post a complete program that demonstrates your problem. Explain what is wrong with its output.
Good Luck,
Bill

jaimitoc30
Novice

Apr 10, 2012, 1:09 PM

Post #3 of 6 (1417 views)

Re: [BillKSmith] Perl regex help. [In reply to]	Can't Post

In Reply To

I must not understand your problem. I have prepared a complete perl program to demonstrate my understanding of it.

Code

use strict; 
use warnings; 
my @samples = ( 
    'acti',  
    'baja',  
    'info', 
    '5.00 65436765', 
    '10.00 65436765',  
); 
my $regex1 = 
    qr/^\s*([0-9]{1,2}[]{0,1}|[0-5]{1,2}[][0,5]{0,1}[0]{0,1})\s+([0-9]{8})\s*$/; 
my $regex2 = 
    qr/^\s*([0-9]{1,2}[]{0,1}|[0-5]{1,2}[][0,5]{0,1}[0]{0,1})\s+([0-9]{8})| 
       (acti|baja|info)\s*$ 
      /x;  
 
foreach my $text (@samples) { 
    if ($text =~ $regex1) { 
        print "Regex_1 Matched: $text\n"; 
    } 
    if ($text =~ $regex2) { 
        print "Regex_2 Matched: $text\n"; 
    } 
}

Ok, I have tested it:

localhost# perl regexval2.pl
Regex_2 Matched: acti
Regex_2 Matched: baja
Regex_2 Matched: info
Regex_1 Matched: 5.00 65436765
Regex_2 Matched: 5.00 65436765
Regex_1 Matched: 10.00 65436765
Regex_2 Matched: 10.00 65436765

Now, look at this code:

Code

#!/usr/local/bin/perl 
 
$text="acti"; 
$text =~ qr/^\s*([0-9]{1,2}[]{0,1}|[0-5]{1,2}[][0,5]{0,1}[0]{0,1})\s+([0-9]{8})|  
       (acti|baja|info)\s*$  
      /x; 
$text= $1; 
print "RESULT: $text\n"; 
print "END";

The result is this:

localhost# perl regexval.pl
RESULT:
END

it won't match, I did a copy paste.. whats the difference then??

BillKSmith
Veteran

Apr 10, 2012, 3:33 PM

Post #4 of 6 (1409 views)

Re: [jaimitoc30] Perl regex help. [In reply to]	Can't Post

The answer to your last question is easy. It does match. The result you want is in $3, not $1. You can fix this problem by replacing all your parenthesis with non-capturing parenthesis and add one set of parenthesis around the entire regex to capture the final result.

I do not get the same result from regexval2.pl as you do. You are probably using a newer version of perl. (I am using ActiveState perl v5.8.8 - Sorry if I misled you in my original post)
Good Luck,
Bill

jaimitoc30
Novice

Apr 11, 2012, 7:39 AM

Post #5 of 6 (1364 views)

Re: [BillKSmith] Perl regex help. [In reply to]	Can't Post

Don't worry at all. Thank you very much for your assistance, I was able to resolve this by using this code:

Code

$text="5.00 66851169"; 
my $regex2 = qr/^\s*([0-9]{1,2}[]{0,1}|[0-5]{1,2}[][0,5]{0,1}[0]{0,1})\s+([0-9]{8})| (acti|baja|info)\s*$ /x; 
$text =~ $regex2; 
print "RESULT: $text\n"; 
print "END";

Thank you very much for your time and assistance.

Regards,
Jaime

rovf
Veteran

Apr 12, 2012, 4:13 AM

Post #6 of 6 (1251 views)

Re: [jaimitoc30] Perl regex help. [In reply to]	Can't Post

I don't think that this regexp really (i.e. in *every* case does exactly what you want it to do. Note that this regexp contains the following sequence of characters:

Code

 .... []{0,1} ....

The closing bracket symbol ']' in this case does NOT close the opening bracket to its left. This is a special rule that a closing bracket immediately following an open bracket, means a literal closing bracket.

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