How can I convert a equation into an character array?

Question

Emre Sahin 2018-10-17

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/424543-how-can-i-convert-a-equation-into-an-character-array

编辑： Emre Sahin 2018-10-20

Hi community,

I want to convert an equation like: N=1-X into an character array like: Z='N=1-X' or the other way around. The problem is functions like string2num() do not accept variables as input.

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Guillaume 2018-10-19

Again, as Matt asked, what form does the equation takes in your code? There are many ways to code an equation for plotting and the answer is going to depend on how you've done it.

Emre Sahin 2018-10-19

编辑：Emre Sahin 2018-10-20

在 MATLAB Online 中打开

I don't exactly know what you mean, I will just show an example code:

 classdef Formfunctions < handle
    methods(Static)  
        function surfplot(handles,X,Y,N)
            s=surf(X,Y,N);
            s.FaceColor='interp';
            a=gca;
            a.Box='on';
            zlim([0 1]);
            xlabel('x')
            ylabel('y')
            % I want to display the function instead of N %
            zlabel('N')
            % I want to show the function N on the static text field%
            set(handles.text,'string', N)
        end
        function Node1plot(handles,X,Y)  
            %Nr.1%
            N1=1/4*(1-X).*(1-Y);
            figure('Name','Plot Formfunctions: Node1plot',...
                   'NumberTitle','off', 'Units', 'Normalized', ...
                   'OuterPosition', [0.5 0 0.5 1]);
            colormap(jet)
            Formfunctions.surfplot(handles,X,Y,N1)
        end
        function Node2plot(handles,X,Y)  
            %Nr.2%
            N2=1/4*(1+X).*(1-Y);
            figure('Name','Plot Formfunction: Node2plot',...
                   'NumberTitle','off', 'Units', 'Normalized', ...
                   'OuterPosition', [0.5 0 0.5 1]);
            colormap(jet)
            Formfunctions.surfplot(handles,X,Y,N2)
        end  
    end
end

In the main function I will just have the comands:

    if(blabla==bla)
       Formfunctions.Node1plot(handles,X,Y);
    elseif(blabla==blala)
       Formfunctions.Node2plot(handles,X,Y); 
    end

I hope that it is know clear.

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Answer 1

Matt J 2018-10-19

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/424543-how-can-i-convert-a-equation-into-an-character-array#answer_342335

编辑：Matt J 2018-10-19

    methods(Static)  
        function surfplot(handles,X,Y,fun)  %<---change
            s=surf(X,Y,fun(X,Y));
            s.FaceColor='interp';
            a=gca;
            a.Box='on';
            zlim([0 1]);
            xlabel('x')
            ylabel('y')
            % I want to display the function instead of N %

            N=strrep( func2str(fun) ,'@(x,y)','' );  %<---change
            zlabel( N )
            % I want to show the function N on the static text field%
            set(handles.text,'string', N)
        end

        function Node1plot(handles,X,Y)

            fun=@(x,y) 1/4*(1-x).*(1-y);  %<---change

            figure('Name','Plot Formfunctions: Node1plot',...
                   'NumberTitle','off', 'Units', 'Normalized', ...
                   'OuterPosition', [0.5 0 0.5 1]);
            colormap(jet)
            Formfunktionen.surfplot(handles,X,Y,fun)  %<---change
        end