MATLAB Answers

## How to plot multiple values of a variable in one graph?

Asked by James Sheldon

### James Sheldon (view profile)

on 12 Jun 2018
Latest activity Commented on by James Sheldon

### James Sheldon (view profile)

on 20 Jun 2018
I put 5 txt files into a loop to graph the FFT and PDS continuously. They are audio files converted to txt files. I used "findpeaks" to find all peaks in the graphs. I then used "max" to find the max peak in each of the 5 graphs. I got 5 answers for the same variable. (l=max(v)). How do I plot all of these answers in one graph? Below is an example of my work. Here is the values I received for the max for each graph, l = 7.1537e+08, l = 1.3054e+09, l = 2.4736e+09, l = 3.4960e+09, l = 2.4039e+09
numfiles = 5;
y = cell(1, numfiles);
for k = 1:numfiles
myfilename = sprintf('file%d.txt', k);
y{k} = importdata(myfilename);
plot(y{k})
m=(abs(fft(y{k})));
%n=m(1:y{k}/2);
%plot(n);
pwelch(y{k})
v= pwelch(y{k})
plot(v)
xlim([0 4000])
findpeaks(v)
l= max(v)
end

Matt Dickson

### Matt Dickson (view profile)

on 12 Jun 2018
To clarify, you want to plot the maximum value (you call it l). What are you plotting it against? Index of the file?
James Sheldon

### James Sheldon (view profile)

on 12 Jun 2018
yes

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## 2 Answers

### Arun Mathamkode (view profile)

Answer by Arun Mathamkode

### Arun Mathamkode (view profile)

on 15 Jun 2018

I believe you want to plot the maximum value for each graph against the index file. You can simply store maximum values in l as an array and plot the array.
In the loop, change l=max(v) to l(k)=max(v) and use plot(l) after the loop.

James Sheldon

### James Sheldon (view profile)

on 20 Jun 2018
This is not exactly what I want. I want to plot the values in a somewhat waterfall type graph so I can stack up numerous values against one another to find the peak value. I will use this to set limits. So I want to plot each 1 values against the max height reached.
James Sheldon

### James Sheldon (view profile)

on 20 Jun 2018
I want more of a scatter plot of the data so I can compare the results.

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### James Sheldon (view profile)

Answer by James Sheldon

### James Sheldon (view profile)

on 19 Jun 2018

Okay. I will try that and see how it turns out. Thank you.

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