Plotting matrix columns

I was able to do this in the past but forgot how I did it. Starting with a 2D matrix I was able to plot it with the first column as the X axis and generate individual sub plots of the remanining columns. Each column was its own plot with the 1st column as the X axis. A loop could do this but I seem to remember it was a simple command that put multiple plots in one figure window. Do I need to plot this as3D surface and then extract slices from the figure?

[Helga Gomes]

Hi, This is exactly the situation that I have and if i wasnt such a novice to Matlab I probably would have figured it out but I cant seem to. I too have the first column in excel which I want to use as my X axis and the next few as my Y axis. I want to be able to plot individual sub plots (different plots as jpeg or any other format) with my 1st column as my X axis every time but I want the Y axis to change as the remaining cols. I would like this to be a loop. but i dont know how to start by reading my xls or asci format file and then adding the loop.

Answer 1

[Sean de Wolski]

doc hold

To plot multiple thingies

figure;
hold on
for ii = 1:10
 plot(matrix(:,ii))
end

[Sara Nouri]

thank you.

Answer 2

[Fangjun Jiang]

Example like this?

a=[1:10;sin(1:10);cos(1:10)]';
subplot(2,1,1);plot(a(:,1),a(:,2));
subplot(2,1,2);plot(a(:,1),a(:,3));

[Mark]

This is similar to what I need. The command was able to make the multiple plots without having to manually request each coloumn or use a loop.

[Fangjun Jiang]

I am not aware a built-in function to do that. Is it possible that you were using a customized function built upon subplot()? Such as:

function AutoSubPlot(a)

N=size(a,2);

if N<2,error('incorrect dimension');end

for i=1:N-1

subplot(N-1,1,i);plot(a(:,1),a(:,i+1));

end

Then, you can all this AutoSubPlot() function:

a=[1:10;sin(1:10);cos(1:10);sin(1:10);cos(1:10)]';

AutoSubPlot(a);

Answer 3

[Stephen23]

It is not clear if you really require subplots, and the other answers are mixed on this too... If the plots are to be on the same axes, then this is very easy, as plot already plots column-wise:

>> A = [1,2,3,4,5; 1,0,1,2,1; 2,1,0,1,2].'
A =
   1     1     2
   2     0     1
   3     1     0
   4     2     1
   5     1     2
>> plot(A(:,1), A(:,2:end)) % first column is the x-values

produces this figure:

[Helga Gomes]

Thanks Stephen, I am really struggling with the basics. My first column is the wavelength and then next two columns are the duplicate absorbance readings related to that wavelength for one particular depth in the water column. I wasnt to plot these two on one single graph to check how my data looks before i do anything else. Then i want to go to next two columns (duplicate absorbance readings for next depth in water column) snd plot these on ANOTHER GRAPH to see how they look. But i dont know how to write the loop. These loops always seem to challenge me.

[MOHAMED AMINE ZOUHRI]

Thanks Stephen

[mayank awasthi]

Hello, Thanks for the simple solution but can you please inform me how can I put legends in this. And what if we have more Y columns.

Answer 4

[Nina]

Hi all, I have a question regarding the surface plotting. I have a matrix, where the first row is my x direction and the first column is my y direction. The values in between are the velocities of each point. Based on this matrix I want to create a 3D plot, where one axis is my x-direction, the second axis is my y-direction and the third axis is the velocity changes. Does anybody have an idea how should I do this?

[KL]

something like

[X,Y] = meshgrid(your_data(1,2:end),your_data(2:end,1))
contour(X,Y,your_data(2:end,2:end))

[Nina]

Thank you so much for your answer. It worked :)