How do I combine multiple plots in one graph?

Hi, is there somewhere I can see some examples of scripts that result in multiple plots on one graph?
I know the 'hold' function is part of how to do it, but I'm very new to Matlab and I really need to see some full examples.
If someone could point me towards some that'd be great.

3 个评论

snr=0:1:15;
for ii=1:length(snr)
x=randint(1,100000); % Generating bits
y=pskmod(x,2); % Generating BPSK modulated data
ynoisy=awgn(y,snr(ii)); % Adding AWGN noise to data
z=pskdemod(ynoisy,2); % Demodulating
error(ii)=length(find(x-z~=0));
end
semilogy(snr,error)
hold
snr=0:1:15;
for ii=1:length(snr)
x=randint(1,100000); % Generating bits
y=pskmod(x,4); % Generating QPSK modulated data
ynoisy=awgn(y,snr(ii)); % Adding AWGN noise to data
z=pskdemod(ynoisy,4); % Demodulating
error(ii)=length(find(x-z~=0));
end
semilogy(snr,error)
grid
You can use this code, but to have multiple plots, you need the subplot which is used as follows:
% Code used in my paper on design of composite riser
% Create a vertical bar chart using the bar function
figure
subplot(2,3,1) % add fourth plot in 2 x 3 grid
bar(1:18, [FibreControl' FibreAxial'], 1)
% Add title and axis labels
title('(a)')
xlabel('Composite Riser Layers')
ylabel('Stress in Fibre Direction (MPa)')
% Add a legend
legend('[1.58:1.62:1.86]', '[1.84:1.62:1.86]')
% Set the axis limits
set(gca, 'XTick', 1:18)
set(gca, 'XLim', [0,19])
set(gca, 'Fontsize', 8)
subplot(2,3,2) % add first plot in 2 x 3 grid
bar(1:18, [FibreControl' FibreAngled'], 1)
% Add title and axis labels
title('(b)')
xlabel('Composite Riser Layers')
ylabel('Stress in Fibre Direction (MPa)')
% Add a legend
legend('[1.58:1.62:1.86]', '[1.58:1.88:1.86]')
% Set the axis limits
set(gca, 'XTick', 1:18)
set(gca, 'XLim', [0,19])
set(gca, 'fontname','arial','fontsize',8,'linewidth',1)
subplot(2,3,3) % add second plot in 2 x 3 grid
bar(1:18, [FibreControl' FibreHoop'], 1)
% Add title and axis labels
title('(c)')
xlabel('Composite Riser Layers')
ylabel('Stress in Fibre Direction (MPa)')
% Add a legend
legend('[1.58:1.62:1.86]', '[1.58:1.62:1.60]')
% Set the axis limits
set(gca, 'XTick', 1:18)
set(gca, 'XLim', [0,19])
set(gca, 'Fontsize', 8)
Hey, @tayyaba, I have to plot graphs of various iterations into the same graph, and the labels are written during each iteration. My problem is that the legend gets overwritten each time instead of being appended to the already existing legend. soln?
semilogy(snr,error(i));
Label=append('Error',error(i));
label(Label);
hold on;

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 采纳的回答

To combine multiple plots in one graph, use the “hold on” command, such as:
plot(1:10)
hold on
plot(11:20)
hold off
For more information, see:

3 个评论

The alternative to "hold on" that would be applicable to this example is
plot(t,x,'r',t,y,'b')
Hello, what other letters can we use if we have more than two functions to plot?
This is the list from the help call:
Various line types, plot symbols and colors may be obtained with
plot(X,Y,S) where S is a character string made from one element
from any or all the following 3 columns:
b blue . point - solid
g green o circle : dotted
r red x x-mark -. dashdot
c cyan + plus -- dashed
m magenta * star (none) no line
y yellow s square
k black d diamond
w white v triangle (down)
^ triangle (up)
< triangle (left)
> triangle (right)
p pentagram
h hexagram

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更多回答(6 个)

x = -3:0.1:3;
y1 = sin(x);
y2 = cos(x);
y3= tan(x);
y4=1./cos(x);
figure
subplot(2,2,1)
plot(x,y1)
title('Subplot 1')
subplot(2,2,2)
plot(x,y2)
title('Subplot 2')
subplot(2,2,3)
plot(x,y3)
title('Subplot 3')
subplot(2,2,4)
plot(x,y4)
title('Subplot 4')

1 个评论

How can we run many simulations at the same time? (for example for 1000 simulations)
or
How can we plot more than 100 graphs in one plot?

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Could you please tell me the same with scatter plot command? That is, to plot multiple scatter plots in one figure?

3 个评论

x=rand(2,10);
scatter(x(1,:),x(2,:),'r');
hold on
x=rand(2,10);
scatter(x(1,:),x(2,:),'g');
hold on
x=rand(2,10);
scatter(x(1,:),x(2,:),'b');
hold on
x=rand(2,10);
scatter(x(1,:),x(2,:),'c');
You can plot multiple plot just use "hold on" command
can I get best fit line from this method?
"can I get best fit line from this method?"
Best fit lines tend to imply an ordering to the data, but scatter plots tend to imply the data might not be ordered in a way that is compatible with fitting.
But yes, if you have polynomial coefficients for your fit, such as coefficients generated using polyfit(), then you can use polyval() to interpolate values, and you can "hold on" and plot() the values.

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How do I plot multiple graphs on the same graph using this code?:
hold off
[x, y] = meshgrid(0:0.2:10, 0:0.2:6);
X = x(1,1:51);
dx = ones(size(x));
dy = x;
quiver(x, y, dx, dy)
axis tight
hold on
plot(X, 1+X.^2/2)

1 个评论

That code already plots multiple lines on the same plot. However, the y range of the second one is much larger than the y range of the first, so the second one takes up most of the space.

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In chemistry, the pH of an aqueous solution is a measure of its acidity. The pH scale ranges from 0 to 14, inclusive. A solution with a pH of 7 is said to be neutral, a solution with a pH greater than 7 is basic, and a solution with a pH less than 7 is acidic.
I did it, but my prof said it is not professional. How to do it professionally?
%% Chapter 8 Question 19
%% This script cteats the a vector structure mysol with various solutions
%% and their pH-values and adds another field mysol.acidity.
clear
clc
format compact
mysol(3) = struct('name','bleach','pH',12);
mysol(1) = struct('name','juce','pH',5);
mysol(2) = struct('name','milk','pH',7);
acidity = myacidity(mysol);
for i = 1:3
mysol(i).acidity = strcat(acidity(i,:));
end
mysol
mysol.acidity
function acidity = myacidity(mysol)
% This function receives a vector structure with various solutions and
% their pH-values and determines acidity of solutions.
len = length(mysol);
acidity(len,:) = blanks(7);
for i = 1:len
if mysol(i).pH < 7
acidity(i,:) = 'acidic ';
elseif mysol(i).pH > 7
acidity(i,:) = 'basic ';
else
acidity(i,:) = 'neutral';
end
end
end

2 个评论

How is this an answer to Tom's question on "multiple plots on one graph"? I think you need to start your own question rather than post an answer to Tom's question.
The line
mysol(i).acidity = strcat(acidity(i,:));
should probably be rewritten in terms of strtrim()

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One must use hold on command after every plot,
plot(x1,y1);
hold on
plot(x2,y2);
hold on
plot(x3,y3);
hold off
This will give output as three plots on a same graph.

1 个评论

This is not correct. "hold on" stays in effect until you turn it off (or the axes is cleared or deleted.)

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