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Run python script in Qt

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  • N Offline
    N Offline
    NotYourFan
    wrote on last edited by
    #9

    @J-Hilk whats the Right path separator?

    J.HilkJ 1 Reply Last reply
    0
    • N NotYourFan

      @J-Hilk whats the Right path separator?

      J.HilkJ Online
      J.HilkJ Online
      J.Hilk
      Moderators
      wrote on last edited by J.Hilk
      #10

      @NotYourFan
      https://en.wikipedia.org/wiki/Filename#Reserved_characters_and_words


      backslash or probably double backslash


      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.

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      • N Offline
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        NotYourFan
        wrote on last edited by
        #11
        This post is deleted!
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        • N Offline
          N Offline
          NotYourFan
          wrote on last edited by
          #12

          okay, thx for your Suggestion.

          void TestWindow::loadFile()
              QProcess p;
              QStringList params;
          
              params << "C:\\development\\Qt\\ProjektXY\\createJSON.py";
              p.start("C:\\development\\Python\\Python37\\python.exe", params);
              p.waitForFinished(-1);
              QString p_stdout = p.readAll();
          

          i tried one time with Backslash and one time with double Backslash … same Problem.

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          • J.HilkJ J.Hilk

            @NotYourFan since you're on windows, you're using the wrong path separator

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

            @J.Hilk said in Run python script in Qt:

            since you're on windows, you're using the wrong path separator

            With Qt / should work on Windows as well, shouldn't it?

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

            J.HilkJ aha_1980A 2 Replies Last reply
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            • jsulmJ jsulm

              @J.Hilk said in Run python script in Qt:

              since you're on windows, you're using the wrong path separator

              With Qt / should work on Windows as well, shouldn't it?

              J.HilkJ Online
              J.HilkJ Online
              J.Hilk
              Moderators
              wrote on last edited by
              #14

              @jsulm I'm unsure

              usually yes, but in this case you're trying to start a System program from the OS. Until now, I've always only used it to start an external program, that I shipped with the other Qt installation and therefore was always at the same depth as the main executable or it was on a unix system...

              @NotYourFan
              have you seen this thread ?
              https://stackoverflow.com/questions/15127047/qt-calling-external-python-script

              It may help you


              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.

              aha_1980A 1 Reply Last reply
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              • jsulmJ jsulm

                @J.Hilk said in Run python script in Qt:

                since you're on windows, you're using the wrong path separator

                With Qt / should work on Windows as well, shouldn't it?

                aha_1980A Offline
                aha_1980A Offline
                aha_1980
                Lifetime Qt Champion
                wrote on last edited by
                #15

                @jsulm

                With Qt / should work on Windows as well, shouldn't it?

                It is really important to use forward slashes for Qt functions, yes. However, the parameter for python (the path to the script) is not evaluated from Qt but from the python interpreter, so here backslashes might be needed.

                That gives:

                params << "C:\\development\\Qt\\ProjektXY\\createJSON.py";
                p.start("C:/Development/Python/Python37/python.exe", params);
                

                Looks funny, though.

                p.waitForFinished(-1); I would use a SLOT here.

                And for testing: can you just try python -c 'print "Hello World"' first?

                Qt has to stay free or it will die.

                1 Reply Last reply
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                • J.HilkJ J.Hilk

                  @jsulm I'm unsure

                  usually yes, but in this case you're trying to start a System program from the OS. Until now, I've always only used it to start an external program, that I shipped with the other Qt installation and therefore was always at the same depth as the main executable or it was on a unix system...

                  @NotYourFan
                  have you seen this thread ?
                  https://stackoverflow.com/questions/15127047/qt-calling-external-python-script

                  It may help you

                  aha_1980A Offline
                  aha_1980A Offline
                  aha_1980
                  Lifetime Qt Champion
                  wrote on last edited by
                  #16

                  @J.Hilk said in Run python script in Qt:

                  usually yes, but in this case you're trying to start a System program from the OS

                  As said, the path for QProcess should work with forward slash. The path for the parameter (the script) probably not.

                  Qt has to stay free or it will die.

                  1 Reply Last reply
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                  • N Offline
                    N Offline
                    NotYourFan
                    wrote on last edited by
                    #17

                    @J-Hilk thank you for the stackoverflow link, i've seen it and try it.
                    @aha_1980 i test python -c 'print "Hello World"' --> i get Nothing.

                    aha_1980A 1 Reply Last reply
                    0
                    • N NotYourFan

                      @J-Hilk thank you for the stackoverflow link, i've seen it and try it.
                      @aha_1980 i test python -c 'print "Hello World"' --> i get Nothing.

                      aha_1980A Offline
                      aha_1980A Offline
                      aha_1980
                      Lifetime Qt Champion
                      wrote on last edited by
                      #18

                      @NotYourFan said in Run python script in Qt:

                      @aha_1980 i test python -c 'print "Hello World"' --> i get Nothing.

                      How did you test it?

                      Qt has to stay free or it will die.

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

                        put python -c 'print "Hello World"' in p.start

                        Pablo J. RoginaP jsulmJ JonBJ 3 Replies Last reply
                        0
                        • N NotYourFan

                          put python -c 'print "Hello World"' in p.start

                          Pablo J. RoginaP Offline
                          Pablo J. RoginaP Offline
                          Pablo J. Rogina
                          wrote on last edited by
                          #20

                          @NotYourFan just in case, you may want to use Python embedded in your Qt application...

                          Upvote the answer(s) that helped you solve the issue
                          Use "Topic Tools" button to mark your post as Solved
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                          • N NotYourFan

                            put python -c 'print "Hello World"' in p.start

                            jsulmJ Offline
                            jsulmJ Offline
                            jsulm
                            Lifetime Qt Champion
                            wrote on last edited by
                            #21

                            @NotYourFan It doesn't work like this. You have to put the command as first parameter to start() and all parameters for the command as parameter list.

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

                            Gojir4G 1 Reply Last reply
                            1
                            • jsulmJ jsulm

                              @NotYourFan It doesn't work like this. You have to put the command as first parameter to start() and all parameters for the command as parameter list.

                              Gojir4G Offline
                              Gojir4G Offline
                              Gojir4
                              wrote on last edited by
                              #22

                              @jsulm Are you sure about that ?
                              from Qt Doc:

                              QProcess process;
                              process.start("del /s *.txt");
                              
                              1 Reply Last reply
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                              • N Offline
                                N Offline
                                NotYourFan
                                wrote on last edited by NotYourFan
                                #23

                                @jsulm i readed in the Qt Doc.
                                @Gojir4 you are right.
                                @Pablo-J-Rogina thx for your Suggestion … but i should / want to do it with QProcess …

                                1 Reply Last reply
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                                • SGaistS Offline
                                  SGaistS Offline
                                  SGaist
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #24

                                  Hi,

                                  @NotYourFan just in case, did you try to compare the environment variables of your QProcess object and the one you have when running e.g. from a terminal ?

                                  @Gojir4 You are right about that specific overload, but the documentation also states that this overload should be avoided if possible.

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

                                  Gojir4G 1 Reply Last reply
                                  2
                                  • SGaistS SGaist

                                    Hi,

                                    @NotYourFan just in case, did you try to compare the environment variables of your QProcess object and the one you have when running e.g. from a terminal ?

                                    @Gojir4 You are right about that specific overload, but the documentation also states that this overload should be avoided if possible.

                                    Gojir4G Offline
                                    Gojir4G Offline
                                    Gojir4
                                    wrote on last edited by
                                    #25

                                    @SGaist My bad. Thanks for clarification !

                                    1 Reply Last reply
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                                    • N NotYourFan

                                      put python -c 'print "Hello World"' in p.start

                                      JonBJ Offline
                                      JonBJ Offline
                                      JonB
                                      wrote on last edited by
                                      #26

                                      @NotYourFan
                                      I am lost as to where you are now.

                                      Assuming it's still crashing --- is that right? --- surely you want to break it down to simplify now. Start with:

                                          params << "-V";
                                          p.start("C:\\development\\Python\\Python37\\python.exe", params);
                                          p.waitForFinished(-1);
                                          QString p_stdout = p.readAll();
                                      

                                      What exactly happens?

                                      1 Reply Last reply
                                      2
                                      • N Offline
                                        N Offline
                                        NotYourFan
                                        wrote on last edited by
                                        #27

                                        @JonB, i get a error Message: ….

                                        ModuleNotFoundError: No module named 'encodings'
                                        
                                        JonBJ 1 Reply Last reply
                                        0
                                        • N NotYourFan

                                          @JonB, i get a error Message: ….

                                          ModuleNotFoundError: No module named 'encodings'
                                          
                                          JonBJ Offline
                                          JonBJ Offline
                                          JonB
                                          wrote on last edited by JonB
                                          #28

                                          @NotYourFan
                                          OK! So, you can forget about your createJSON.py script and anything it does.

                                          I don't know why you get this when spawning from Qt but not when running your python.exe directly from a command prompt. Either it's something to do with it sending output to a pipe you are reading from, or it's to do with your general Python environment being different between the two situations.

                                          You want now to Google for python ModuleNotFoundError: No module named 'encodings'. There are posts/suggestions. Looks to me like it might be to do with whether you are using a virtual environment or not, but I'm sure one of the hits will sort you out....

                                          aha_1980A 1 Reply Last reply
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