fscanf - In an assignment A(I) = B, the number of elements in B and I must be the same.

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Darryl 2014-9-23

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回答： dpb 2014-9-23

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I cannot get fscanf to work with my Arduino when plotting a graph in real-time. I've read the docs and cannot see where I am going wrong.

I have 4 Arduino Serial.println statements. 3 of which are strings which I don't need. The 4th is an integer which is what I want to plot in real-time.

Here is my code:

ard = serial('/dev/tty.usbserial-A601EQJ5', 'BaudRate', 9600);
fopen(ard);
i = 1;
N = 50;
x = zeros(0, N);
while i <= N
     x(i) = fscanf(ard, '%*s %d');
     plot(x)
     hold on
     axis([1, N, 0, 150])
     drawnow;
     i = i + 1;
end

I keep getting the error that I have written in my title no matter what I change.

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dpb 2014-9-23

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x(i) = fscanf(ard, '%*s %d');

x(i) is a single entry; apparently there are either no returned values or more than one reading is available from the fscanf call. Try

x(i) = fscanf(ard, '%*s %d',1);

to read just one return value at a time.

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