create many bar plots with loop process

Hello!!

I need your help for an issue I had...

I have two matrixes

A --> 20x50 double

B -->20x50 double

and I want to create bar plots for the first rows of A and B, the secont bar plot will be the second rows of A and B etc... So I have to create 20 "grouped" bar plots from the respective rows of A and B

the x axis should be a cell array 1x50: 1, 2, 3, .... ,50+

I managed to create each bar plot without loop process but I was wondering how would be the code if I used a for loop to do all the bar plots ones and save them as a tif?

Thank you in advance

Answer 1

[Scott MacKenzie]

A = rand(20,50);
B = rand(20,50);
x = 1:50;

for i=1:size(A,1)    
    bar(x,[A(i,:); B(i,:)]);
    filename = sprintf('plot_%02d.tif', i);
    print(filename, '-dtiff');
end

You can't use a cell array for the x-axis. You can for the x-axis tick labels. Perhaps that's what you meant.

[Giannis Nikolopoulos]

Hello mr. MacKenzie,

thanks you very much for your reply.

It is very interesting this tiled layout but how can I take all this charts separately? I mean 20 separate barplots and consequently save 20 different tiffs

thanks you again

Giannis

[Scott MacKenzie]

I just modified my code to save each plot in a separate tif file.

[Giannis Nikolopoulos]

Thank you very much!!

[Giannis Nikolopoulos]

@Scott MacKenzie

Hello!!

there is an error when I running this code to my matlab

it says (red colored):

Error using bar (line 168)

the length of X must match the number of rows of Y

Error in barplot_test (line 6)

bar(x,[A(i,:); B(i,:)];

when I clicked on "line 168" it opens the core code of 'bar'...i dont kwon why

Do you have any idea?

thanks in advance

[Giannis Nikolopoulos]

i used the Matlab 2019a

[Scott MacKenzie]

Hmmm, that's odd. Seems the constraints on bar have changed since R2019a. The equivalent error message now is "the length of X must match the number of rows or columns of Y".

Try changing

x = 1:50;

to

x = 1:20;

Another thing to try is removing the x-argument from the bar function:

bar([A(i,:); B(i,:)]);

In this form, the x-argument is implicit. Good luck.

Answer 2

[Adam Danz]

If you want all 20 axes on the same figure, the bars will be quite tightly packed. Consider breaking up groups of axes into separate figures.

• This uses TiledLayout to create the axes with compact spacing.
• The edge lines of the bar are removed so you can see more of the bar colors.
• The axes are all linked so their axis limits are all the same - this can be removed if you don't want to have identical axis limits for all axes.

% Create demo data
A = rand(20,50) .* linspace(1,10,50) + linspace(0,2,20)'; 
B = rand(20,50) .* linspace(1,12,50) + linspace(0,3,20)'; 

fig = figure(); 
tlo = tiledlayout(fig, 'flow','Padding','compact','TileSpacing','compact'); 
nPlots = size(A,1); 
ax = gobjects(1,nPlots); 
for i = 1:nPlots
   ax(i) = nexttile(tlo);
   bh = bar([A(i,:)', B(i,:)'],'Grouped','EdgeColor','none');
   bh(1).FaceColor = 'r'; 
   bh(2).FaceColor = 'b'; 
   title(ax(i), sprintf('Row %d',i))
end

linkaxes(ax)
leg = legend(ax(end),{'A','B'},'Orientation','Horizontal');
leg.Layout.Tile = 'south';

Right-click and open the image in a new window to see full size.

Option 2: use connected scatter plot

This version uses vertical lines to connect the heights of each bar rather than showing the groupped bars. It therefore has more space between groups since the groups are vertically stacked. This demo uses a different random dataset than above.

A = rand(20,50) .* linspace(1,10,50) + linspace(0,2,20)'; 
B = rand(20,50) .* linspace(1,12,50) + linspace(0,3,20)'; 


fig = figure(); 
tlo = tiledlayout(fig, 'flow','Padding','compact','TileSpacing','compact'); 
nPlots = size(A,1); 
ax = gobjects(1,nPlots); 
x = 1:size(A,2); 
for i = 1:nPlots
   ax(i) = nexttile(tlo);
   hold (ax(i), 'on')
   plot([x;x],[A(i,:); B(i,:)], 'k-s','MarkerFaceColor','w','MarkerSize',4)
   sh = scatter(x,[A(i,:); B(i,:)],16,[1 0 0; 0 0 1],'filled','MarkerFaceAlpha', .5,'MarkerEdgeColor', 'none','Marker', 's');   title(ax(i), sprintf('Row %d',i))
   box(ax(i),'on')
   axis(ax(i),'tight')
   grid(ax(i),'on')
end

linkaxes(ax)
leg = legend(ax(end),sh,{'A','B'},'Orientation','Horizontal');
leg.Layout.Tile = 'south';

Right-click and open the image in a new window to see full size.