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Regex doesn't seem to work with Qt

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  • Petross404_Petros SP Petross404_Petros S

    Hello guys, I hope you are doing well. I am trying to create a regex in order to filter some text:

    Symbols from "/mnt/home/petros/test".
    Local exec file:
            `/mnt/home/petros/test', file type elf64-x86-64.
            Entry point: 0x1050
            0x0000000000000318 - 0x0000000000000334 is .interp
            0x0000000000000338 - 0x0000000000000368 is .note.gnu.property
            0x0000000000000368 - 0x0000000000000388 is .note.ABI-tag
            0x0000000000000388 - 0x00000000000003ac is .gnu.hash
            0x00000000000003b0 - 0x0000000000000458 is .dynsym
            0x0000000000000458 - 0x00000000000004da is .dynstr
            0x00000000000004da - 0x00000000000004e8 is .gnu.version
            0x00000000000004e8 - 0x0000000000000508 is .gnu.version_r
            0x0000000000000508 - 0x00000000000005c8 is .rela.dyn
            0x00000000000005c8 - 0x00000000000005e0 is .rela.plt
            0x0000000000001000 - 0x0000000000001017 is .init
            0x0000000000001020 - 0x0000000000001040 is .plt
            0x0000000000001040 - 0x0000000000001048 is .plt.got
            0x0000000000001050 - 0x00000000000011d9 is .text
            0x00000000000011dc - 0x00000000000011e5 is .fini
            0x0000000000002000 - 0x0000000000002017 is .rodata
            0x0000000000002018 - 0x0000000000002054 is .eh_frame_hdr
            0x0000000000002058 - 0x0000000000002144 is .eh_frame
            0x0000000000003db8 - 0x0000000000003dc0 is .init_array
            0x0000000000003dc0 - 0x0000000000003dc8 is .fini_array
            0x0000000000003dc8 - 0x0000000000003fb8 is .dynamic
            0x0000000000003fb8 - 0x0000000000004000 is .got
            0x0000000000004000 - 0x0000000000004010 is .data
            0x0000000000004010 - 0x0000000000004018 is .bss
    

    This regex here (/file type.*/g) filters correctly what I am trying to do. Basically I will delete the "file type " part later and keep only the "elf64-x86-64." but that's ok.

    When I try to create this regex with Qt though it doesn't seem to work:

        QRegExp re{"//file type.*//g"};    // Even without escaping it, it doesn't capture anything.
        QString str{output};               //This is the wall of text above.
        
    
        qDebug() << re.capturedTexts();                    // ("")
        qDebug() << "exact match? " << re.exactMatch(str); // exact match?  false
    

    So my question is does Qt5 have a different syntax for regular expressions or am I missing something else here?

    JonBJ Offline
    JonBJ Offline
    JonB
    wrote on last edited by JonB
    #5

    @Petross404_Petros-S said in Regex doesn't seem to work with Qt:

    QRegExp re{"//file type.*//g"}; // Even without escaping it, it doesn't capture anything.

    Given you're using QRegExp (wouldn't make any difference if QRegularExpression anyway). Where did you get the idea this is suitable input for it? It is not.

    So my question is does Qt5 have a different syntax for regular expressions or am I missing something else here?

    This regex here (/file type.*/g)

    You seem to be assuming that what you see on that page you reference is literally what you can use elsewhere. Though even then you have changed it. And you seem to have selected for JavaScript.

    Petross404_Petros SP 1 Reply Last reply
    0
    • JonBJ JonB

      @Petross404_Petros-S said in Regex doesn't seem to work with Qt:

      QRegExp re{"//file type.*//g"}; // Even without escaping it, it doesn't capture anything.

      Given you're using QRegExp (wouldn't make any difference if QRegularExpression anyway). Where did you get the idea this is suitable input for it? It is not.

      So my question is does Qt5 have a different syntax for regular expressions or am I missing something else here?

      This regex here (/file type.*/g)

      You seem to be assuming that what you see on that page you reference is literally what you can use elsewhere. Though even then you have changed it. And you seem to have selected for JavaScript.

      Petross404_Petros SP Offline
      Petross404_Petros SP Offline
      Petross404_Petros S
      wrote on last edited by
      #6

      @JonB said in Regex doesn't seem to work with Qt:

      @Petross404_Petros-S said in Regex doesn't seem to work with Qt:

      QRegExp re{"//file type.*//g"}; // Even without escaping it, it doesn't capture anything.

      Given you're using QRegExp (wouldn't make any difference if QRegularExpression anyway). Where did you get the idea this is suitable input for it? It is not.

      So my question is does Qt5 have a different syntax for regular expressions or am I missing something else here?

      This regex here (/file type.*/g)

      You seem to be assuming that what you see on that page you reference is literally what you can use elsewhere. Though even then you have changed it. And you seem to have selected for JavaScript.

      Oh sorry then, how could I miss this?

      1 Reply Last reply
      0
      • VRoninV Offline
        VRoninV Offline
        VRonin
        wrote on last edited by VRonin
        #7

        the /g is not how you set the regex to global

        const QRegularExpression regExp(QStringLiteral(R"***(file type.*)***"));
        QRegularExpressionMatchIterator regExpMatch =  regExp.globalMatch(input);
        while (regExpMatch .hasNext()) {
            const QRegularExpressionMatch match = regExpMatch .next();
            qDebug() <<  match.capturedRef(0);
        }
        

        "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
        ~Napoleon Bonaparte

        On a crusade to banish setIndexWidget() from the holy land of Qt

        Petross404_Petros SP 1 Reply Last reply
        0
        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #8

          Hi,

          Are you trying to use file glob pattern ?

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

          Petross404_Petros SP 1 Reply Last reply
          0
          • VRoninV VRonin

            the /g is not how you set the regex to global

            const QRegularExpression regExp(QStringLiteral(R"***(file type.*)***"));
            QRegularExpressionMatchIterator regExpMatch =  regExp.globalMatch(input);
            while (regExpMatch .hasNext()) {
                const QRegularExpressionMatch match = regExpMatch .next();
                qDebug() <<  match.capturedRef(0);
            }
            
            Petross404_Petros SP Offline
            Petross404_Petros SP Offline
            Petross404_Petros S
            wrote on last edited by
            #9

            @VRonin said in Regex doesn't seem to work with Qt:

            the /g is not how you set the regex to global

            const QRegularExpression regExp(QStringLiteral(R"***(file type.*)***"));
            QRegularExpressionMatchIterator regExpMatch =  regExp.globalMatch(input);
            while (regExpMatch .hasNext()) {
                const QRegularExpressionMatch match = regExpMatch .next();
                qDebug() <<  match.capturedRef(0);
            }
            

            Yes, it seems that it needed a different approach. This works:

            QString str{output};  //The output from the first post.
            
            const QRegularExpression regExp(QStringLiteral(R"***(file type.*)***"));
            QRegularExpressionMatch regExpMatch =  regExp.match(str);
            
            QString strFileType {regExpMatch.captured(0)};   //"file type elf64-x86-64."
            
            if(strFileType.contains("file type") && strFileType.contains("."))
            {
                strFileType.replace("file type ", "");
                strFileType.replace(".", "");
            }
            
            That was a little
            qDebug() << strFileType;                       // "elf64-x86-64"
            

            Thank you all.

            VRoninV 1 Reply Last reply
            0
            • SGaistS SGaist

              Hi,

              Are you trying to use file glob pattern ?

              Petross404_Petros SP Offline
              Petross404_Petros SP Offline
              Petross404_Petros S
              wrote on last edited by
              #10

              @SGaist said in Regex doesn't seem to work with Qt:

              Hi,

              Are you trying to use file glob pattern ?

              Yes but in the wrong way. Thank you for your interest.

              1 Reply Last reply
              0
              • Petross404_Petros SP Petross404_Petros S

                @VRonin said in Regex doesn't seem to work with Qt:

                the /g is not how you set the regex to global

                const QRegularExpression regExp(QStringLiteral(R"***(file type.*)***"));
                QRegularExpressionMatchIterator regExpMatch =  regExp.globalMatch(input);
                while (regExpMatch .hasNext()) {
                    const QRegularExpressionMatch match = regExpMatch .next();
                    qDebug() <<  match.capturedRef(0);
                }
                

                Yes, it seems that it needed a different approach. This works:

                QString str{output};  //The output from the first post.
                
                const QRegularExpression regExp(QStringLiteral(R"***(file type.*)***"));
                QRegularExpressionMatch regExpMatch =  regExp.match(str);
                
                QString strFileType {regExpMatch.captured(0)};   //"file type elf64-x86-64."
                
                if(strFileType.contains("file type") && strFileType.contains("."))
                {
                    strFileType.replace("file type ", "");
                    strFileType.replace(".", "");
                }
                
                That was a little
                qDebug() << strFileType;                       // "elf64-x86-64"
                

                Thank you all.

                VRoninV Offline
                VRoninV Offline
                VRonin
                wrote on last edited by
                #11

                @Petross404_Petros-S said in Regex doesn't seem to work with Qt:

                strFileType.contains(".")

                . in regexp has a special menaing. if you want to match the literal dot you have to escape it

                "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                ~Napoleon Bonaparte

                On a crusade to banish setIndexWidget() from the holy land of Qt

                Petross404_Petros SP 1 Reply Last reply
                1
                • VRoninV VRonin

                  @Petross404_Petros-S said in Regex doesn't seem to work with Qt:

                  strFileType.contains(".")

                  . in regexp has a special menaing. if you want to match the literal dot you have to escape it

                  Petross404_Petros SP Offline
                  Petross404_Petros SP Offline
                  Petross404_Petros S
                  wrote on last edited by Petross404_Petros S
                  #12

                  @VRonin said in Regex doesn't seem to work with Qt:

                  @Petross404_Petros-S said in Regex doesn't seem to work with Qt:

                  strFileType.contains(".")

                  . in regexp has a special menaing. if you want to match the literal dot you have to escape it

                  Interesting because it actually removed the dot. When I used it like " \. " it didn't work.
                  EDIT It doesn't show the \ characters I used above.

                  1 Reply Last reply
                  0
                  • VRoninV Offline
                    VRoninV Offline
                    VRonin
                    wrote on last edited by
                    #13

                    My bad, I wasn't clear. . in QRegularExpression mean any character.

                    strFileType.replace(".", ""); is correct but unnecessary:

                    QString str{output};  //The output from the first post.
                    
                    const QRegularExpression regExp(QStringLiteral(R"***(file type\s*(.*)\.)***"));
                    QRegularExpressionMatch regExpMatch =  regExp.match(str);
                    qDebug() << regExpMatch.captured(0);   //"file type elf64-x86-64."
                    QString strFileType = regExpMatch.captured(1);
                    qDebug() << strFileType; //"elf64-x86-64"
                    

                    "La mort n'est rien, mais vivre vaincu et sans gloire, c'est mourir tous les jours"
                    ~Napoleon Bonaparte

                    On a crusade to banish setIndexWidget() from the holy land of Qt

                    1 Reply Last reply
                    0
                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #14

                      QRegularExpression::wildcardToRegularExpression is what you were looking for.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                      Petross404_Petros SP 1 Reply Last reply
                      3
                      • SGaistS SGaist

                        QRegularExpression::wildcardToRegularExpression is what you were looking for.

                        Petross404_Petros SP Offline
                        Petross404_Petros SP Offline
                        Petross404_Petros S
                        wrote on last edited by
                        #15

                        @SGaist said in Regex doesn't seem to work with Qt:

                        QRegularExpression::wildcardToRegularExpression is what you were looking for.

                        I am afraid I can't use this function since it is very recent and compatiblity with Qt5.4 is needed. But thank you.

                        @VRonin thank you too, your example was to the point. I will take a deeper look at what you did there. Thanks again.

                        1 Reply Last reply
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