Error using sscanf Invalid format.

this is my code and i am gettin the above mentioned error help would be apreciated

        % Button pushed function: SelectFileButton
        function SelectFileButtonPushed(app, event)
            [F,P] = uigetfile();
            Results1 = fullfile(P,F);
            Results2 = fopen(Results1);
            Results4 = [0,0,0];
            FlowRatePulse = [];
            Pressure = [];
            n = 0;
            Time = 0;
            while n >= 0
                n = n+1;
                Results3 = fgetl(Results2);
                Results5 = sscanf(Results3,Results4);

                Pressure(n) =((-0.2+Results5(1,1))/0.0018)/5;
                FlowRatePulse(n) = Results5(1,2)/330;
                Time = Time + Results5(1,3);
                
                
                
            end
            plot(app.UIAxes,Pressure,FlowRatePulse,'o')
            plot(app.UIAxes2,Time,Pressure,'o')
            plot(app.UIAxes3,Time,FlowRatePulse,'o')
        end

[Stephen23]

I note that you have already fixed your previous unrelated error using the answer that I gave you, but have not accepted the answer. On this forum it is considered polite to accept an answer when it resolves your original question.

[Jordan Stocker]

didnt know about that thanks for telling me that did work by the way

Answer 1

[Stephen23]

The sscanf documentation explains its syntax as "A = sscanf(str,formatSpec) reads data from str, converts it according to the format specified by formatSpec..." and also specifies that " formatSpec can be a character vector in single quotes, or a string scalar."

Rather than following what the documentation requires, you have defined the format specifier as the numeric vector [0,0,0]. Instead of a numeric vector, you should be providing a character vector or a string scalar, as the documentation states. The documentation also has plenty of examples of the format specifier.

[Jordan Stocker]

the aim of the sscsnf is to remove the V counts and ms from the numbers so that the numbers may be used in calculations later

would this work

Results4 = (V:counts:ms);

or is there a better way to be doing this

[Stephen23]

One way would be to download my FEX submission sip2num and use that on the complete file string, e,g.:

>> str = fileread('Gradual opening of tap.txt');
>> mat = sip2num(str); % converts '500 m' to 0.5
>> mat = reshape(mat,3,[]).'
mat =
      0.36168            0          0.5
      0.35679            0          0.5
      0.36168            0          0.5
      0.36168            0          0.5
      0.36657            0          0.5
      0.36168            0          0.5
      0.36168            0          0.5
      0.36168            0          0.5
      0.36168            0          0.5
      0.36168            0          0.5
      0.35679            0          0.5
      0.35679            0          0.5
      0.36168            0          0.5
      0.35679            0          0.5
      0.36168            0          0.5
      0.35679            0          0.5
      0.35679            0          0.5
      0.34702            1          0.5
      0.35191            3          0.5
      0.35679            4          0.5
      0.36168            3          0.5
      0.35191            4          0.5
      0.35191            4          0.5
      0.35191            4          0.5
... lots more lines here
      0.29814           35          0.5
      0.30303           35          0.5
      0.29326           35          0.5
      0.30303           35          0.5
      0.29814           34          0.5
      0.29814           35          0.5
      0.30303           35          0.5
      0.30303           35          0.5
>> 

If you really want to use fscanf or sscanf then you will need to define a suitable format string, e.g.:

>> mat = sscanf(str,'%f V,%f counts,%f ms',[3,Inf]).'
mat =
      0.36168            0          500
      0.35679            0          500
      0.36168            0          500
      0.36168            0          500
      0.36657            0          500
      0.36168            0          500
      0.36168            0          500
      0.36168            0          500
      0.36168            0          500
      0.36168            0          500
      0.35679            0          500
      0.35679            0          500
      0.36168            0          500
      0.35679            0          500
      0.36168            0          500
      0.35679            0          500
      0.35679            0          500
      0.34702            1          500
      0.35191            3          500
      0.35679            4          500
      0.36168            3          500
      0.35191            4          500
      0.35191            4          500
... lots more lines here
      0.30303           35          500
      0.29326           35          500
      0.30303           35          500
      0.29814           34          500
      0.29814           35          500
      0.30303           35          500
      0.30303           35          500
>>