Unwanted line on plot
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I am plotting real time data and I have a continually updating plot. I want to show 50 points on the graph and update as more data comes in. Here is currently what I am doing:
while 1
for i=1:50
plot(x,y)
end
end
Now the problem with this is that once the for loop gets back to the first element, on the plot there is a line that connects the left most data point to the right most data point and continues until the program is stopped.
Is there anyway to get around this line?
EDIT: Adding the complete example
count = 0;
while count < 3
for i = 1 : 30
num1 = rand + 1;
Out1(i) = num1;
c=clock;
Time(i)=(c(5)+(c(6)/100));
plot(Time,Out1)
drawnow();
end
count = count + 1;
end
1 Comment
Jan
on 28 Feb 2012
The posted code does not reproduce the problem, because x and y are not defined. Perhaps you simply wand "plot(x,y,'0')", but this is not clear.
Accepted Answer
Jiro Doke
on 29 Feb 2012
Is this what you're looking for?
count = 0;
Out1 = nan(1, 30);
Time = nan(1, 30);
while count < 3
for i = 1 : 30
num1 = rand + 1;
c=clock;
Out1 = [Out1(2:end), num1];
Time = [Time(2:end), (c(5)+(c(6)/60))];
plot(Time,Out1)
pause(0.1);
end
count = count + 1;
end
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More Answers (3)
Jiro Doke
on 29 Feb 2012
[Old Answer]
You're seeing that behavior because you have data points remaining from the previous loop. You can reset the variables Out1 and Time.
count = 0;
while count < 3
Out1 = nan(1, 30);
Time = nan(1, 30);
for i = 1 : 30
num1 = rand + 1;
Out1(i) = num1;
c=clock;
Time(i)=(c(5)+(c(6)/100));
plot(Time,Out1)
drawnow();
end
count = count + 1;
end
BTW, this is called Preallocation which is a good practice when you're assigning values to an array in a loop.
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