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remove any int from a string

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  • A Offline
    A Offline
    Asperamanca
    wrote on last edited by Asperamanca
    #2

    Depends on what exactly you want.
    Suppose you have this string:
    Total: 6.99
    What should be the result?
    a) Total: 6.99 (because "6.99" is not an integer when taken as a whole)
    b) Total: . (Numbers removed, separator remains)
    c) Total: (Whole number including separator removed)

    You might want to take a look at QString::removeIf or a QString::replace overload that takes a regular expression (any number), in which case you can replace it with nothing.

    1 Reply Last reply
    4
    • R Ruben12313

      Hello all, quick question

      How can I remove all int numbers from a QString?
      example:

      QString line = ui->comboBox->currenText();
      

      and I get say : Blueberry 2012

      I just want to delete the numbers and store Blueberry.

      Ive tried:
      ```
      line.removeAt('\t');
      line.truncate(9);

      JonBJ Offline
      JonBJ Offline
      JonB
      wrote on last edited by
      #3

      @Ruben12313
      As @Asperamanca says. Decide on your rules for what exactly constitutes a "number" or "int" and then use QString &QString::replace(const QRegularExpression &re, const QString &after) to replace your target regular expression for the number/int by an empty string. As an example, to remove all sequences of one or more digits, with an optional preceding minus sign, for "int":

      QString s = "Blueberry 2012";
      s.replace(QRegularExpression("-?\\d+"), "");
      

      In your case you might want to include space character in what you remove, else you'll end up with "Blueberry ".

      1 Reply Last reply
      4
      • R Ruben12313

        Hello all, quick question

        How can I remove all int numbers from a QString?
        example:

        QString line = ui->comboBox->currenText();
        

        and I get say : Blueberry 2012

        I just want to delete the numbers and store Blueberry.

        Ive tried:
        ```
        line.removeAt('\t');
        line.truncate(9);

        Pl45m4P Offline
        Pl45m4P Offline
        Pl45m4
        wrote on last edited by
        #4

        @Ruben12313 said in remove any int from a string:

        I get say : Blueberry 2012

        Does the text you get from there always have a similar style like "ABC" + "space/tab" + number?
        Then it might be easier to cut after the separator, as you have tried with removeAt('\t') and you're done.
        Otherwise you have to parse the string without numeric characters (see @JonB 's solution using RegEx)

        Btw: There are no integers in a string. Numeric characters in a string are interpreted as text string and don't have the numeric value they represent.
        "A" directly converted to int is 65 (or 0x41), while
        "65" as numeric string is 54 53 (or 0x36 0x35)

        See "ASCII" and "Integer to String conversion".


        If debugging is the process of removing software bugs, then programming must be the process of putting them in.

        ~E. W. Dijkstra

        R 1 Reply Last reply
        1
        • Pl45m4P Pl45m4

          @Ruben12313 said in remove any int from a string:

          I get say : Blueberry 2012

          Does the text you get from there always have a similar style like "ABC" + "space/tab" + number?
          Then it might be easier to cut after the separator, as you have tried with removeAt('\t') and you're done.
          Otherwise you have to parse the string without numeric characters (see @JonB 's solution using RegEx)

          Btw: There are no integers in a string. Numeric characters in a string are interpreted as text string and don't have the numeric value they represent.
          "A" directly converted to int is 65 (or 0x41), while
          "65" as numeric string is 54 53 (or 0x36 0x35)

          See "ASCII" and "Integer to String conversion".

          R Offline
          R Offline
          Ruben12313
          wrote on last edited by Ruben12313
          #5

          @Pl45m4 yes i only gave blueberry as an example but its a videogame score board:
          (playername 5842) when i used removeAT('\t') it did nothing.

          Pl45m4P 1 Reply Last reply
          0
          • R Ruben12313

            @Pl45m4 yes i only gave blueberry as an example but its a videogame score board:
            (playername 5842) when i used removeAT('\t') it did nothing.

            Pl45m4P Offline
            Pl45m4P Offline
            Pl45m4
            wrote on last edited by Pl45m4
            #6

            @Ruben12313 said in remove any int from a string:

            when i used removeAT('\t') it did nothing.

            Because space (' ' ) is not tab (\t).


            If debugging is the process of removing software bugs, then programming must be the process of putting them in.

            ~E. W. Dijkstra

            1 Reply Last reply
            1
            • R Offline
              R Offline
              Ruben12313
              wrote on last edited by
              #7

              Hey @Pl45m4 @Asperamanca @JonB

              I went for a for loop but got a slight error : conversion from 'int' to 'QChar' is ambiguous

                  auto numb= line1.length();
                  for(int i = 0; i < numb; ++i)
                  {
                      if (line1.at(i) == 8 )
                      {
                          line1.removeAt(i);
                      }
                  }
              
              1 Reply Last reply
              0
              • SGaistS Offline
                SGaistS Offline
                SGaist
                Lifetime Qt Champion
                wrote on last edited by
                #8

                Hi,

                Why not search from the end of the string for the first white space character ?

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

                R 1 Reply Last reply
                1
                • SGaistS SGaist

                  Hi,

                  Why not search from the end of the string for the first white space character ?

                  R Offline
                  R Offline
                  Ruben12313
                  wrote on last edited by
                  #9

                  @SGaist said in remove any int from a string:

                  search from the end of the string for the first white space character

                  Do you have any examples for me to check out? My thing is that in my temp GUI user inputs their name and after the game ends I add the score (lilith k 9876) or (matthew thorn 98739) and I have to update the scores every time they play. So far i can do everything except delete the old score before adding the new one.

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                  0
                  • SGaistS Offline
                    SGaistS Offline
                    SGaist
                    Lifetime Qt Champion
                    wrote on last edited by
                    #10

                    QString::lastIndexOf

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

                    R 1 Reply Last reply
                    1
                    • SGaistS SGaist

                      QString::lastIndexOf

                      R Offline
                      R Offline
                      Ruben12313
                      wrote on last edited by
                      #11

                      @SGaist solved thanks

                          QString name = line1;
                          int pos = name.lastIndexOf(QChar(' '));
                          qDebug() << name.left(pos);
                      
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                      0
                      • R Ruben12313 has marked this topic as solved on
                      • sierdzioS Offline
                        sierdzioS Offline
                        sierdzio
                        Moderators
                        wrote on last edited by
                        #12

                        Depends how generic you want to do it. If you want to remove all numbers from the entire string, something like this should work (although I'm not sure if it will work for big UTF-8 chars):

                        const auto line = ui->comboBox->currenText();
                        QString result;
                        
                        for (const auto &character : line) {
                          if (character.isDigit() == false) {
                            result.append(character);
                          }
                        }
                        

                        (Z(:^

                        SGaistS 1 Reply Last reply
                        0
                        • sierdzioS sierdzio

                          Depends how generic you want to do it. If you want to remove all numbers from the entire string, something like this should work (although I'm not sure if it will work for big UTF-8 chars):

                          const auto line = ui->comboBox->currenText();
                          QString result;
                          
                          for (const auto &character : line) {
                            if (character.isDigit() == false) {
                              result.append(character);
                            }
                          }
                          
                          SGaistS Offline
                          SGaistS Offline
                          SGaist
                          Lifetime Qt Champion
                          wrote on last edited by
                          #13

                          @sierdzio this does not take into account player names with numbers in them such as FooBar666 ;-)

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

                          1 Reply Last reply
                          0
                          • sierdzioS Offline
                            sierdzioS Offline
                            sierdzio
                            Moderators
                            wrote on last edited by
                            #14

                            Oh sorry I was looking at some old version of this post :D Forgot to refresh the window, I didn't notice there are other replies already.

                            Yes my code will remove all digits in the entire string.

                            (Z(:^

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