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Get the string between two delimiters only.

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  • Paul ColbyP Paul Colby

    Hi @mbatra,

    I want to get all the strings only between ':' and ',' delimiters.

    Here's two options.

    The first uses QString::split() to split on the : and then trims everything after the ,:

        const auto parts = str.split(QLatin1Char(':')).mid(1);
        for (const auto &part: parts) {
            const QString item = part.left(part.indexOf(QLatin1Char(',')));
            qDebug() << item;
        }
    

    Option 2 uses regex to define the actual content you want to capture:

        const static QRegularExpression pattern(QStringLiteral(":([^,]*),"));
        for (auto iter = pattern.globalMatch(str); iter.hasNext(); ) {
            qDebug() << iter.next().captured(1);
        }
    

    They are both identical for your test string, both outputting:

    "SSIBRDBUNO"
    "AUG2101001"
    "374"
    "320"
    "100"
    "100"
    "200"
    "1"
    ""
    "234"
    "01082021"
    "01082021"
    "0000001"
    "0000000"
    "0000001"
    "1"
    "01082021"
    "01082021"
    "1"
    

    But they will differ on some input corner cases. Which one is "more correct" will depend on your specific use case/s.

    Cheers.

    M Offline
    M Offline
    mbatra
    wrote on last edited by
    #3

    @Paul-Colby

    Hi Paul,

    Thanks for your response. Its working fine with both the methods. Just one more help, the first method is fine for me:
    const auto parts = str.split(QLatin1Char(':')).mid(1);
    for (const auto &part: parts) {
    const QString item = part.left(part.indexOf(QLatin1Char(',')));
    qDebug() << item;
    }

    as I need the last string "1@3237472528!" also. But I need only 1 which is before '@' character. How to split the last string after ':' and before '@'.

    Thanks.

    Paul ColbyP 1 Reply Last reply
    0
    • M mbatra

      @Paul-Colby

      Hi Paul,

      Thanks for your response. Its working fine with both the methods. Just one more help, the first method is fine for me:
      const auto parts = str.split(QLatin1Char(':')).mid(1);
      for (const auto &part: parts) {
      const QString item = part.left(part.indexOf(QLatin1Char(',')));
      qDebug() << item;
      }

      as I need the last string "1@3237472528!" also. But I need only 1 which is before '@' character. How to split the last string after ':' and before '@'.

      Thanks.

      Paul ColbyP Offline
      Paul ColbyP Offline
      Paul Colby
      wrote on last edited by
      #4

      as I need the last string "1@3237472528!"

      Oh right, the regex version didn't include that entry. To make them identical, the regex should have been:

          const static QRegularExpression pattern(QStringLiteral(":([^,]*)(,|$)"));
      

      But I need only 1 which is before '@' character. How to split the last string after ':' and before '@'.

      Well, it depends a bit on how definitive your example is... ie can random @ characters appear elsewhere in the string? It doesn't appear so (in your sample string), in which case either of these will do the trick:

      Split version:

          const QString item = part.left(part.indexOf(QLatin1Char(','))).left(part.indexOf(QLatin1Char('@')));
      

      Regex version:

          const static QRegularExpression pattern(QStringLiteral(":([^,]*)[,@]"));
      

      Again, which approach is better depends on the other possible variations of your input.

      Cheers.

      M 2 Replies Last reply
      2
      • Paul ColbyP Paul Colby

        as I need the last string "1@3237472528!"

        Oh right, the regex version didn't include that entry. To make them identical, the regex should have been:

            const static QRegularExpression pattern(QStringLiteral(":([^,]*)(,|$)"));
        

        But I need only 1 which is before '@' character. How to split the last string after ':' and before '@'.

        Well, it depends a bit on how definitive your example is... ie can random @ characters appear elsewhere in the string? It doesn't appear so (in your sample string), in which case either of these will do the trick:

        Split version:

            const QString item = part.left(part.indexOf(QLatin1Char(','))).left(part.indexOf(QLatin1Char('@')));
        

        Regex version:

            const static QRegularExpression pattern(QStringLiteral(":([^,]*)[,@]"));
        

        Again, which approach is better depends on the other possible variations of your input.

        Cheers.

        M Offline
        M Offline
        mbatra
        wrote on last edited by
        #5

        @Paul-Colby
        Hi Paul,

        Thank you very much for your response.

        @Paul-Colby said in Get the string between two delimiters only.:

        Well, it depends a bit on how definitive your example is... ie can random @ characters appear elsewhere in the string? It doesn't appear so (in your sample string), in which case either of these will do the trick:

        No, '@' will not appear elsewhere in the string. This worked fine.

        Thanks.

        1 Reply Last reply
        0
        • Paul ColbyP Paul Colby

          as I need the last string "1@3237472528!"

          Oh right, the regex version didn't include that entry. To make them identical, the regex should have been:

              const static QRegularExpression pattern(QStringLiteral(":([^,]*)(,|$)"));
          

          But I need only 1 which is before '@' character. How to split the last string after ':' and before '@'.

          Well, it depends a bit on how definitive your example is... ie can random @ characters appear elsewhere in the string? It doesn't appear so (in your sample string), in which case either of these will do the trick:

          Split version:

              const QString item = part.left(part.indexOf(QLatin1Char(','))).left(part.indexOf(QLatin1Char('@')));
          

          Regex version:

              const static QRegularExpression pattern(QStringLiteral(":([^,]*)[,@]"));
          

          Again, which approach is better depends on the other possible variations of your input.

          Cheers.

          M Offline
          M Offline
          mbatra
          wrote on last edited by
          #6

          @Paul-Colby

          Hi Paul,

          Its working fine. I am facing one issue. Earlier I had created a QString and saved it in csv file as below:

          QFile file("D:\data.csv");
          if(file.open(QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text ))
          {
          QTextStream out(&file);
          out << query7; // query7 is a QString.
          }

          But when I tried to insert item into csv file it doesn't store in csv format, it stores the entire string into one column.

          QFile file("D:\\v1.7\\data.csv");
          file.open(QIODevice::ReadWrite | QIODevice::Append | QIODevice::Text );
          
          const auto parts = str.split(QLatin1Char(':')).mid(1);
          for (const auto &part: parts) {
              //const QString item = part.left(part.indexOf(QLatin1Char(',')));
              const QString item = part.left(part.indexOf(QLatin1Char(','))).left(part.indexOf(QLatin1Char('@')));
              qDebug() << "item :"<<item;
          
              QTextStream out(&file);
              out << item;
          }
          

          Can you help me to resolve this issue.

          Thanks.

          jsulmJ 2 Replies Last reply
          0
          • M mbatra

            @Paul-Colby

            Hi Paul,

            Its working fine. I am facing one issue. Earlier I had created a QString and saved it in csv file as below:

            QFile file("D:\data.csv");
            if(file.open(QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text ))
            {
            QTextStream out(&file);
            out << query7; // query7 is a QString.
            }

            But when I tried to insert item into csv file it doesn't store in csv format, it stores the entire string into one column.

            QFile file("D:\\v1.7\\data.csv");
            file.open(QIODevice::ReadWrite | QIODevice::Append | QIODevice::Text );
            
            const auto parts = str.split(QLatin1Char(':')).mid(1);
            for (const auto &part: parts) {
                //const QString item = part.left(part.indexOf(QLatin1Char(',')));
                const QString item = part.left(part.indexOf(QLatin1Char(','))).left(part.indexOf(QLatin1Char('@')));
                qDebug() << "item :"<<item;
            
                QTextStream out(&file);
                out << item;
            }
            

            Can you help me to resolve this issue.

            Thanks.

            jsulmJ Offline
            jsulmJ Offline
            jsulm
            Lifetime Qt Champion
            wrote on last edited by
            #7

            @mbatra said in Get the string between two delimiters only.:

            one column

            One column or one line? If one line simply write a new line into the file after each line.
            Also, why do you create QTextStream instance inside the loop? This is wasting CPU cycles for nothing.

            https://forum.qt.io/topic/113070/qt-code-of-conduct

            M 1 Reply Last reply
            0
            • jsulmJ jsulm

              @mbatra said in Get the string between two delimiters only.:

              one column

              One column or one line? If one line simply write a new line into the file after each line.
              Also, why do you create QTextStream instance inside the loop? This is wasting CPU cycles for nothing.

              M Offline
              M Offline
              mbatra
              wrote on last edited by
              #8

              @jsulm

              Hi,

              One String in each column. I have moved QTextStream outside the loop for now.
              But All strings are comin in one column only.

              jsulmJ 1 Reply Last reply
              0
              • M mbatra

                @jsulm

                Hi,

                One String in each column. I have moved QTextStream outside the loop for now.
                But All strings are comin in one column only.

                jsulmJ Offline
                jsulmJ Offline
                jsulm
                Lifetime Qt Champion
                wrote on last edited by
                #9

                @mbatra Can you show how it should look like and what you really get?

                https://forum.qt.io/topic/113070/qt-code-of-conduct

                M 2 Replies Last reply
                0
                • jsulmJ jsulm

                  @mbatra Can you show how it should look like and what you really get?

                  M Offline
                  M Offline
                  mbatra
                  wrote on last edited by
                  #10

                  @jsulm

                  f5b4617e-3079-4660-a32a-32e80913b031-image.png

                  I am getting like this.
                  Each string should be stored in different columns.

                  JonBJ 1 Reply Last reply
                  0
                  • jsulmJ jsulm

                    @mbatra Can you show how it should look like and what you really get?

                    M Offline
                    M Offline
                    mbatra
                    wrote on last edited by
                    #11

                    @jsulm

                    Instead, it should come like this
                    2bb60072-b788-4c92-a1cd-13b52ed621a9-image.png

                    1 Reply Last reply
                    0
                    • M mbatra

                      @jsulm

                      f5b4617e-3079-4660-a32a-32e80913b031-image.png

                      I am getting like this.
                      Each string should be stored in different columns.

                      JonBJ Offline
                      JonBJ Offline
                      JonB
                      wrote on last edited by JonB
                      #12

                      @mbatra
                      Look in the .csv file, not what Excel or whatever spreadsheet you are using shows you. How are the columns separated in the file? Did you output space, comma or tab or whatever you want/need to separate the strings into columns? "CSV" stands for "comma separated values". In English you need to put commas between the columns, but I have seen in other posts that if your language uses , in floating point numbers for English decimal point (.) then I believe you are supposed to use some other separator.

                      1 Reply Last reply
                      1
                      • M mbatra

                        @Paul-Colby

                        Hi Paul,

                        Its working fine. I am facing one issue. Earlier I had created a QString and saved it in csv file as below:

                        QFile file("D:\data.csv");
                        if(file.open(QIODevice::WriteOnly | QIODevice::Append | QIODevice::Text ))
                        {
                        QTextStream out(&file);
                        out << query7; // query7 is a QString.
                        }

                        But when I tried to insert item into csv file it doesn't store in csv format, it stores the entire string into one column.

                        QFile file("D:\\v1.7\\data.csv");
                        file.open(QIODevice::ReadWrite | QIODevice::Append | QIODevice::Text );
                        
                        const auto parts = str.split(QLatin1Char(':')).mid(1);
                        for (const auto &part: parts) {
                            //const QString item = part.left(part.indexOf(QLatin1Char(',')));
                            const QString item = part.left(part.indexOf(QLatin1Char(','))).left(part.indexOf(QLatin1Char('@')));
                            qDebug() << "item :"<<item;
                        
                            QTextStream out(&file);
                            out << item;
                        }
                        

                        Can you help me to resolve this issue.

                        Thanks.

                        jsulmJ Offline
                        jsulmJ Offline
                        jsulm
                        Lifetime Qt Champion
                        wrote on last edited by
                        #13

                        @mbatra said in Get the string between two delimiters only.:

                        part.left(part.indexOf(QLatin1Char(','))).left(part.indexOf(QLatin1Char('@')));

                        I'm not sure this is correct: you're calling left() and then on the result of that call you again call left but use result from indexOf() from the whole string not the part returned from first left() call.
                        Does qDebug() << "item :"<<item; output what you want?

                        https://forum.qt.io/topic/113070/qt-code-of-conduct

                        M 1 Reply Last reply
                        0
                        • jsulmJ jsulm

                          @mbatra said in Get the string between two delimiters only.:

                          part.left(part.indexOf(QLatin1Char(','))).left(part.indexOf(QLatin1Char('@')));

                          I'm not sure this is correct: you're calling left() and then on the result of that call you again call left but use result from indexOf() from the whole string not the part returned from first left() call.
                          Does qDebug() << "item :"<<item; output what you want?

                          M Offline
                          M Offline
                          mbatra
                          wrote on last edited by
                          #14

                          @jsulm

                          Yes, it outputs as expected. All the strings.
                          But when I write the strings into .csv file, it enters aal the string into one column.

                          jsulmJ 1 Reply Last reply
                          0
                          • M mbatra

                            @jsulm

                            Yes, it outputs as expected. All the strings.
                            But when I write the strings into .csv file, it enters aal the string into one column.

                            jsulmJ Offline
                            jsulmJ Offline
                            jsulm
                            Lifetime Qt Champion
                            wrote on last edited by
                            #15

                            @mbatra Then please do what @JonB suggested: open the file in a text editor. Do you actually write any separator like ',' to separate the columns?

                            https://forum.qt.io/topic/113070/qt-code-of-conduct

                            JonBJ 1 Reply Last reply
                            0
                            • jsulmJ jsulm

                              @mbatra Then please do what @JonB suggested: open the file in a text editor. Do you actually write any separator like ',' to separate the columns?

                              JonBJ Offline
                              JonBJ Offline
                              JonB
                              wrote on last edited by
                              #16

                              @jsulm said in Get the string between two delimiters only.:

                              Do you actually write any separator like ',' to separate the columns?

                              The code indicates that the OP does not....

                              M 1 Reply Last reply
                              0
                              • JonBJ JonB

                                @jsulm said in Get the string between two delimiters only.:

                                Do you actually write any separator like ',' to separate the columns?

                                The code indicates that the OP does not....

                                M Offline
                                M Offline
                                mbatra
                                wrote on last edited by
                                #17

                                @JonB

                                Hi,

                                I have added the separator. Its working fine.

                                Thank you everyone for your support.

                                1 Reply Last reply
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