Re: find function of String

From:
"Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 20 Oct 2010 22:23:05 +0200
Message-ID:
<i9nj3e$9l3$1@speranza.aioe.org>
* coolchap, on 20.10.2010 17:56:

Thank you for all your responses. I guess I am not very clear in my
question. Actually it is nothing complicated. All text except [ or ]
needs to be extracted. there is no complex stuff of subsets etc...


In that case, how about

<code>
#include <algorithm>
#include <iostream>
#include <string>
#include <sstream>

using namespace std;

void analyze( string s )
{
     replace( s.begin(), s.end(), '[', ' ' );
     replace( s.begin(), s.end(), ']', ' ' );

     istringstream stream( s );
     string id, numSpec;

     while( stream >> id >> numSpec )
     {
         cout << id << ' ' << numSpec << endl;
     }
}

int main()
{
     analyze( "[SBD 65 [INI 25 [PUP 0 ][RPN 25 ]][ANA 1 ][BUIPNR0 ][BUIPAX 1 ]" );
}
</code>

?

Anywayz I found a simple way using boost::regex to match only the
characters followed by numbers


   Some people, when confronted with a problem, think ?I know, I'll use regular
   expressions.? Now they have two problems.
   - Jamie Zawinski

int main(int argc, char* argv[])
{
    try
    {
        cout<< "[START REGEXP CHECKING]"<< endl;

        // String to be validated
        string myString = "[SBD 65 [INI 25 [PUP 0 ][RPN 25 ]][ANA 1 ][BUIPNR
0 ][BUIPAX 1 ]";

        // Regular Expression to be used.
        string myRegexp = "[a-zA-Z]+\\s\\d+";
        boost::regex aMyRegExp(myRegexp);

        // Needed to extract some part from myString, considering the sub-
expressions grouped by "()"
        boost::cmatch matches;

        cout<< endl<< "String: "<< myString;
        cout<< endl<< "Regular Expression: "<< myRegexp<< endl;

        // Checking if myString matches the Regular Expression.
        // Use boost::regex_match(myString.c_str(), aMyRegExp) if the
extraction is not needed
        std::string::const_iterator start, end;
        start = myString.begin();
        end = myString.end();
        boost::match_results<std::string::const_iterator> what;
        boost::match_flag_type flags = boost::match_default;
        while (regex_search(start, end, what, aMyRegExp, flags)){
            cout<< "Size: "<< what.size()<< endl;
            cout<< "Result: "<< what<< endl;

            // update start position
            start = what[0].second;
        }

        cout<< endl<< endl<< "[END REGEXP CHECKING]"<< endl;
        return 0;
    }
    catch (...)
    {
        cout<< "EXCEPTION!!!!"<< endl;
        return 1;
    }

}

This prints out only text in the format of XYZ 34 etc


He he... :-)

Cheers & hth.,

- Alf

--
blog at <url: http://alfps.wordpress.com>

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