[rules-users] Extracting data from strings(regular expression)

[Wolfgang Laun]

Well, the pattern matchin will have to be done twice.

With your method you can save the repeated pattern compilation
by creating a static Pattern p = Pattern.compile().

The pattern suggests that it might be possible to do a String.split on
"," and take the String[3] as your group. Also, the pattern itself
might be improved by using

   "3240, Z4 Ph. Reach,[^,]*, ([^]*), ohm, [^,]*, [^,]*, [^,]*"

to avoid repeated backtracking (provided ',' is indeed a true separator).

-W

On 27/08/2012, Qiteng Hong <q.hong at strath.ac.uk> wrote:
> Hi Laune:
> Thanks for your comments and suggestions.
> Actually that's what I am doing . firstly match the string in the LHS and
> then on the RHS I call the java method  parsingZ4_Ph_Reach()--details as
> followed I took it as a compromised solution but not sure how it will
> influence the efficiency. Any idea about this?
>
>
> public double parsingZ4_Ph_Reach(String line){
>>                      String regx="3240, Z4 Ph. Reach, .*, (.*), ohm,  .*,
>> .*, .*";
>>                      Pattern
>> p=Pattern.compile(regx,Pattern.CASE_INSENSITIVE);
>>                      Matcher m =p.matcher(line);
>>                      if(m.matches()){
>>                            return Double.parseDouble(m.group(1));
>>                      }
>>                      return 0;
>>               }
>
> Thx
>
> ----------------------------------------------------------------------------------------------
> QITENG HONG
> PhD Research Student
> Advanced Electrical Systems Group
> Institute of Energy and Environment
> Department of Electronic and Electrical Engineering
> University of Strathclyde
> Glasgow G1 1XW
> The University of Strathclyde is a charitable body, registered in Scotland,
> number SC015263
> ________________________________________
> From: rules-users-bounces at lists.jboss.org
> [rules-users-bounces at lists.jboss.org] On Behalf Of Wolfgang Laun
> [wolfgang.laun at gmail.com]
> Sent: 27 August 2012 17:26
> To: Rules Users List
> Subject: Re: [rules-users] Extracting data from strings(regular expression)
>
> Although there is the "matches" operator, Drools isn't a sophisticated
> regular expression engine.
>
> Once you have matched a fact with a String line that matches some
> regular expression, you'll have to reapply the regular expression on
> the right hand side so that you can extract the string matching group
> 1. Or use simple String methods to extract this information, now that
> you know that the string has a certain pattern.
>
> -W
>
>
>
>
> On 27/08/2012, abing19881226 <q.hong at strath.ac.uk> wrote:
>> Hi:
>> I am trying to match a string to my regular expression and then capture
>> certain groups from the string.
>> I know previously there is no such feature , but I am just wondering if
>> there is one now?
>>
>> Basically , what am trying to do is,  insert strings into the session,
>> and
>> carry out the reasoning to see if matches a certain regular expression.
>> In JAVA I did it as this:
>>
>>
>>        public double parsingZ4_Ph_Reach(String line){
>>                      String regx="3240, Z4 Ph. Reach, .*, (.*), ohm, .*,
>> .*,
>> .*";
>>                      Pattern
>> p=Pattern.compile(regx,Pattern.CASE_INSENSITIVE);
>>                      Matcher m =p.matcher(line);
>>                      if(m.matches()){
>>                            return Double.parseDouble(m.group(1));
>>                      }
>>                      return 0;
>>               }
>>
>>
>> The purpose is to extract the data in the strings using drools.
>> Could you please give me some idea I I could do that in Drools?
>> Many thx.
>>
>>
>>
>>
>>
>> --
>> View this message in context:
>> http://drools.46999.n3.nabble.com/Extracting-data-from-strings-regular-expression-tp4019405.html
>> Sent from the Drools: User forum mailing list archive at Nabble.com.
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>> rules-users mailing list
>> rules-users at lists.jboss.org
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>>
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