Using plot command in a loop

Hey All,

I tried to change the input argument for plot command but it didn't work as I discovered that plot doesn't accept it as an input argument:

for i= 1:20

figure, plot((sprintf('Data%d',i))) , hold on; plot(f_mean*ones(length(sprintf('Data%d',i)),1),'r'); plot(sprintf('alpha_data%d',i),'g'); plot(sprintf('alpha_data_neg%d',i),'g'); hold off; axis ([0 350 0.28 0.32])

end

What can I change in my code to make it work??

[Azzi Abdelmalek]

you are trrying to plot a string. What data do you want to plot?

Answer 1

[Pedro Villena]

if you want to change the variable name in the loop, use eval command

for i= 1:20,
    figure(i),
    eval(sprintf('plot(Data%d)',i));
    hold on;
    eval(sprintf('plot(f_mean*ones(1,length(Data%d)),''r'')',i));
    eval(sprintf('plot(alpha_data%d,''g'')',i));
    eval(sprintf('plot(alpha_data_neg%d,''g'')',i));
    hold off;
    axis ([0 350 0.28 0.32])
end

[Yasmin Tamimi]

Thanks a lot. Really appreciated!

Answer 2

[MANJUNATH]

try using string to num conversion

[Yasmin Tamimi]

Thank you.

Answer 3

[Robert Cumming]

using eval is almost always a bad idea. Store your data as

Data(1), Data(2) etc..... rather than Data1, Data2 etc....

If you end up needing to use eval to solve your problem your looking in the wrong area for a solution.

Why should you not use it:

1. Its hard to debug 2. Its very slow.

Have a look at Matlabs Loren telling you why to avoid eval here and here