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Write at the beginn of a File (.py)

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  • N Offline
    N Offline
    NotYourFan
    wrote on last edited by
    #6

    Oh now i have another problem ...

    at the first four lines are my imports for the script:

    import csv
    import re
    import json
    import math

    i want that to write now "test = 'TestFile.csv'"
    at the fifth line, to looks like this:

    import csv
    import re
    import json
    import math
    
    test = 'TestFile.csv'
    
    jsulmJ J.HilkJ 2 Replies Last reply
    0
    • N NotYourFan

      Oh now i have another problem ...

      at the first four lines are my imports for the script:

      import csv
      import re
      import json
      import math

      i want that to write now "test = 'TestFile.csv'"
      at the fifth line, to looks like this:

      import csv
      import re
      import json
      import math
      
      test = 'TestFile.csv'
      
      jsulmJ Offline
      jsulmJ Offline
      jsulm
      Lifetime Qt Champion
      wrote on last edited by
      #7

      @NotYourFan Then open the file in Append mode and append empty line and the other one...

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

      1 Reply Last reply
      0
      • N Offline
        N Offline
        NotYourFan
        wrote on last edited by
        #8

        With the Append mode i write my stream at the bottem ... thats the Problem.

        JonBJ 1 Reply Last reply
        0
        • N NotYourFan

          With the Append mode i write my stream at the bottem ... thats the Problem.

          JonBJ Offline
          JonBJ Offline
          JonB
          wrote on last edited by JonB
          #9

          @NotYourFan
          @jsulm is getting confused with the example you have given. He is assuming the line you want to add is right at the end, but you mean somewhere in the middle, there is still more stuff after it in the file. Just ignore any mentions of "append".

          Look, as I have said, you're probably best here just reading line-by-line from the old file, inserting whatever you want as you go writing it out to a new file. Then delete original and rename new to old at the end. This is always a good idea, as you don't overwrite your existing file with partial stuff if for whatever reason you have an error in your code or something. This is a common way to alter existing files. Just do it this way....

          A completely separate question is why you want to rewrite an existing Python code file anyway? You may have your reasons. But if we took just your example of "injecting" that line into the source, are you sure it could not be achieved better by passing TestFile.csv on the command line at run time as an argument to your Python executable??

          1 Reply Last reply
          1
          • N NotYourFan

            Oh now i have another problem ...

            at the first four lines are my imports for the script:

            import csv
            import re
            import json
            import math

            i want that to write now "test = 'TestFile.csv'"
            at the fifth line, to looks like this:

            import csv
            import re
            import json
            import math
            
            test = 'TestFile.csv'
            
            J.HilkJ Offline
            J.HilkJ Offline
            J.Hilk
            Moderators
            wrote on last edited by J.Hilk
            #10

            @NotYourFan

            QFile file("C:/Users/Test/Desktop/Projekt/write.py");
            if(file.open(QIODevice::ReadOnly | QIODevice::Text)) {
              QTextStream rstream(&file);
              QVector<QString> v;
               while(! rstream.atEnd())
                    v.append(rstream.readLine());
              file.close();
              if(file.open(QIODevice::WriteOnly | QIODevice::Text)) {
                QTextStream wstream(&file);
            
                for(int i(0); i < v.size(); i++){
                     if( i == 5)
                         wstream <<  "test = 'TestFile.csv' " 
                    wstream << v.at(i);
            
                }
                file.close();
              }
            }
            

            edit: fixed some typos, auto correct can be a pain, sometimes.


            Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


            Q: What's that?
            A: It's blue light.
            Q: What does it do?
            A: It turns blue.

            JonBJ 1 Reply Last reply
            3
            • J.HilkJ J.Hilk

              @NotYourFan

              QFile file("C:/Users/Test/Desktop/Projekt/write.py");
              if(file.open(QIODevice::ReadOnly | QIODevice::Text)) {
                QTextStream rstream(&file);
                QVector<QString> v;
                 while(! rstream.atEnd())
                      v.append(rstream.readLine());
                file.close();
                if(file.open(QIODevice::WriteOnly | QIODevice::Text)) {
                  QTextStream wstream(&file);
              
                  for(int i(0); i < v.size(); i++){
                       if( i == 5)
                           wstream <<  "test = 'TestFile.csv' " 
                      wstream << v.at(i);
              
                  }
                  file.close();
                }
              }
              

              edit: fixed some typos, auto correct can be a pain, sometimes.

              JonBJ Offline
              JonBJ Offline
              JonB
              wrote on last edited by JonB
              #11

              @J.Hilk
              I don't wish to start an argument or sound rude, but why encourage to read the whole file into memory when it's just as simple to do it line by line (at least in OP's case) as you go? Plus read-from-old-write-to-new doesn't suffer from blatting the original when the programmer makes a coding error! :) Anyway it's preference for the OP.

              J.HilkJ 1 Reply Last reply
              1
              • JonBJ JonB

                @J.Hilk
                I don't wish to start an argument or sound rude, but why encourage to read the whole file into memory when it's just as simple to do it line by line (at least in OP's case) as you go? Plus read-from-old-write-to-new doesn't suffer from blatting the original when the programmer makes a coding error! :) Anyway it's preference for the OP.

                J.HilkJ Offline
                J.HilkJ Offline
                J.Hilk
                Moderators
                wrote on last edited by
                #12

                @JonB Simple,
                I took the liberty to copy and past @VRonin example from before and edit it ;-)


                Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                Q: What's that?
                A: It's blue light.
                Q: What does it do?
                A: It turns blue.

                JonBJ 1 Reply Last reply
                1
                • J.HilkJ J.Hilk

                  @JonB Simple,
                  I took the liberty to copy and past @VRonin example from before and edit it ;-)

                  JonBJ Offline
                  JonBJ Offline
                  JonB
                  wrote on last edited by
                  #13

                  @J.Hilk
                  Lol! :) OK, I commented on that earlier, far be it for us to disagree with the venerable @VRonin :) Anyway, the OP can do it either way as he sees fit.

                  1 Reply Last reply
                  0
                  • N Offline
                    N Offline
                    NotYourFan
                    wrote on last edited by
                    #14

                    @J-Hilk

                    Wehen i run your code, my .py scriptcode changed complete to only ONE Row.

                    J.HilkJ 1 Reply Last reply
                    0
                    • N NotYourFan

                      @J-Hilk

                      Wehen i run your code, my .py scriptcode changed complete to only ONE Row.

                      J.HilkJ Offline
                      J.HilkJ Offline
                      J.Hilk
                      Moderators
                      wrote on last edited by
                      #15

                      @NotYourFan
                      the example is not checked, I don't have a +py file for that.

                      Obviously you need to add a new line character at the end of each line.

                      if( i == 5)
                                   wstream <<  "test = 'TestFile.csv' "  << "\n";
                              wstream << v.at(i) << "\n";;
                      

                      Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                      Q: What's that?
                      A: It's blue light.
                      Q: What does it do?
                      A: It turns blue.

                      1 Reply Last reply
                      2
                      • N Offline
                        N Offline
                        NotYourFan
                        wrote on last edited by
                        #16
                        This post is deleted!
                        1 Reply Last reply
                        0
                        • N Offline
                          N Offline
                          NotYourFan
                          wrote on last edited by
                          #17

                          @J-Hilk
                          now it works the problem is when i changed the wstram it doesent override.

                          i get " test = 'Hallo221.csv' test = 'Hallo1.csv' ...."

                          how i can override?

                          thx

                          JonBJ 1 Reply Last reply
                          0
                          • N NotYourFan

                            @J-Hilk
                            now it works the problem is when i changed the wstram it doesent override.

                            i get " test = 'Hallo221.csv' test = 'Hallo1.csv' ...."

                            how i can override?

                            thx

                            JonBJ Offline
                            JonBJ Offline
                            JonB
                            wrote on last edited by
                            #18

                            @NotYourFan
                            What does "override" mean? Do you mean "overwrite" what is already in wstream? Do you mean wstream.seek(0)?

                            1 Reply Last reply
                            0
                            • N Offline
                              N Offline
                              NotYourFan
                              wrote on last edited by
                              #19

                              yeah sry,

                              i mean "overwrite".

                              i always get " test = 'Hallo221.csv' test = 'Hallo1.csv' test = 'Hallo12321.csv' .....

                              but i want to get only "test = 'Hallo12321.csv' so i want to "overwrite" the line 5 and not add a new string

                              JonBJ J.HilkJ 2 Replies Last reply
                              0
                              • N NotYourFan

                                yeah sry,

                                i mean "overwrite".

                                i always get " test = 'Hallo221.csv' test = 'Hallo1.csv' test = 'Hallo12321.csv' .....

                                but i want to get only "test = 'Hallo12321.csv' so i want to "overwrite" the line 5 and not add a new string

                                JonBJ Offline
                                JonBJ Offline
                                JonB
                                wrote on last edited by JonB
                                #20

                                @NotYourFan
                                So did you try my wstream.seek(0)? after the first write and before the second?
                                Or, depending on just what you intend by "overwrite", you may need to wstream.resize(0).
                                Try with both "first-string-is-long", "second-is-short" and then with "first-is-short", "second-string-is-long" to see the difference between seek(0) vs resize(0).

                                1 Reply Last reply
                                0
                                • N NotYourFan

                                  yeah sry,

                                  i mean "overwrite".

                                  i always get " test = 'Hallo221.csv' test = 'Hallo1.csv' test = 'Hallo12321.csv' .....

                                  but i want to get only "test = 'Hallo12321.csv' so i want to "overwrite" the line 5 and not add a new string

                                  J.HilkJ Offline
                                  J.HilkJ Offline
                                  J.Hilk
                                  Moderators
                                  wrote on last edited by J.Hilk
                                  #21

                                  @NotYourFan

                                  You're doing fishy stuff, that may break at any point. 
                                  You should rethink what you're actually trying to do.

                                  for(int i(0); i < v.size(); i++){
                                           if( i == 5) {
                                               wstream <<  "test = 'TestFile.csv' "   << "\n";
                                              if(v.at(i).contains("test = '"))
                                                  continue;
                                           }        
                                           wstream << v.at(i)  << "\n";
                                      }
                                  

                                  Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                                  Q: What's that?
                                  A: It's blue light.
                                  Q: What does it do?
                                  A: It turns blue.

                                  N 1 Reply Last reply
                                  3
                                  • J.HilkJ J.Hilk

                                    @NotYourFan

                                    You're doing fishy stuff, that may break at any point. 
                                    You should rethink what you're actually trying to do.

                                    for(int i(0); i < v.size(); i++){
                                             if( i == 5) {
                                                 wstream <<  "test = 'TestFile.csv' "   << "\n";
                                                if(v.at(i).contains("test = '"))
                                                    continue;
                                             }        
                                             wstream << v.at(i)  << "\n";
                                        }
                                    
                                    N Offline
                                    N Offline
                                    NotYourFan
                                    wrote on last edited by
                                    #22

                                    @J.Hilk
                                    PERFEKT !!!!!
                                    THANK YOU SO MUTCH

                                    1 Reply Last reply
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