How to plot .txt file - matlab

I have a text file with two columns, called Fx1. In column 1 it shows deflection calculations and in column 2 it shows force calculation (about 100).
I loaded the text file into matlab as a variable, called Fx1.
How do I plot this text file as a graph, with deflection as my x value, and force as my y value? Apparently, I am supposed to define my variables, but I do not know how to do so when I'm getting the data from a .txt file.
This is what I did and I did not get the correct graph:
plot(fx1)
Any ideas?
Here is a screenshot of my text file:
Here is my text file. It continues for many values, I just copy and pasted the beginning
Here is a screenshot of my whole workspace, I am trying to make a plot for all txt files between Fx1-Fx9.
Matlab work space


You should separate fx1 into two vector. Use these commands:
x=fx1(:,2)';
y=fx1(:,1)';
plot(x,y);
In additional you can combine these three command to one command:
plot(fx1(:,2)',fx1(:,1)');

Related

Numerical Matrix CSV -> Covariance Matrix

I have a CSV file containing a numerical matrix with over two thousand New York Stock Exchange listed companies' value over two years.
It seems like it should be really simple - I want to attain a covariance matrix formed from the CSV matrix.
As far as I'm aware I simply need to:
Import the data as numerical matrix (just the data no headings etc) using the MATLAB Import Data button.
Press save as on the workspace variable and make e.g. NYSE.mat.
In my function call cov(NYSE.mat);
This should access the matrix and return a large covariance matrix from my data. The cov() function works when i manually input an example matrix of for example:
[5 0 3 7; 1 -5 7 3; 4 9 8 10];
But for some reason whenever I try to call cov(NYSE.mat); only one number is returned, rather than a covariance matrix.
Can anyone tell me where I'm going wrong? I've been trying to figure this out for a while now and I feel the answer should be really simple.
I'm running on MATLAB R2016a.

Not sure you need to manually save the workspace name in step 2. As part of your import process you once you click the import button the variable should be loaded into workspace with the name of the file (maybe NYSE)
Try Load('NYSE.mat') and see what appears in your workspace.
Once you figure out the name of the variable, calling the function with that.

If your CSV file is without any header lines (not sure if any CSV file needs them) and contains only numbers, you can simply call
x = importdata('<nameofyourcsv>.csv');
and then
c = cov(x);
or even do it in one step:
c = cov(importdata('nameofcsv.csv'));
This function is equivalent of clicking on the button you mention. However, if your file contains header lines, you have to specify its number and call this function with more parameters:
x = importdata('nameofcsv.csv',',', nh); % nh is a number of header lines
x will no longer be a regular MATLAB matrix but a structure with following fields: data, textdata, and colheaders. cov(x.data) will calculate covariance. Not sure why you would need to save anything in a mat file, though. If you wish, you would probably need to assign a value from a data field to a regular variable and then save such variable. Otherwise, you will save the whole x structure.
For instance, the following file, test.csv:
95.01,76.21,61.54,40.57,5.79,20.28,1.53
23.11,45.65,79.19,93.55,35.29,19.87,74.68
60.68,1.85,92.18,91.69,81.32,60.38,44.51
48.60,82.14,73.82,41.03,0.99,27.22,93.18
89.13,44.47,17.63,89.36,13.89,19.88,46.60
can be imported by calling importdata:
>> x = importdata('test.csv')
x =
95.0100 76.2100 61.5400 40.5700 5.7900 20.2800 1.5300
23.1100 45.6500 79.1900 93.5500 35.2900 19.8700 74.6800
60.6800 1.8500 92.1800 91.6900 81.3200 60.3800 44.5100
48.6000 82.1400 73.8200 41.0300 0.9900 27.2200 93.1800
89.1300 44.4700 17.6300 89.3600 13.8900 19.8800 46.6000
EDIT
I downloaded the file and copy pasted this command from your answer:
c = importdata('nyse_data_matrix_no_tags.csv');
Then, I opened the file in a text editor and copied 1st and 20th row of numbers in the file and created a matrix in MATLAB:
x = [46.09,24.69,156.78,5.95,21.14,76.17,55.51,7.04,38.87,19.58,47.57,7.73,119.44,1.61,44.55,24.9,50.89,4.87,26.25,15.95,15.96,39.14,121.27,15.7,25.91,25.8,69.7,16.32,12.86,7.89,247.4,27.11,41.6,5.14,47.77,40.98,13.78,26.058,14.56,41.05,24.27,47.13,40.92,27,85.04,15.06,5.05,29.14,7.51,67.5,67.79,42.68,124.86,24.28,27.82,18.08,100.67,109.07,12.59,50.34,18.64,4.75,6.06,16.63,109.86,14.1,54.48,13.9,59.98,16.24,45.53,4.06,67.99,18.22,4.2,117.23,158.75,5.7,2.46,76.39,77.79,6.17,16.95,5.27,12.74,14.7,19.14,14.4,42.77,26.4,14.17,76.57,12.4,42.07,77.47,41.27,60.53,16.97,65.71,56.13,258.4,28.96,760.07,60.46,34.77,133.1,14.19,29.41,11.78,154.55,44.75,15.18,17.52,24.86,36.18,14.1,30.1,47.65,22.92,47.37,61.84,226.52,10.2,65.14,7.88,16.34,170.23,9.6,34.42,15.0999,20.34,58.7,16.6,14.72,14.32,20.89,14.32,13.2,6.05,422.96,21.43,47.55,13.28,27.98,8.16,45.15,15.1665,41.65,17.45,25.73,63.03,16.07,17.56,11.54,6.54,33.18,15.01,357.96,74.88,15.24,27.24,69.08,36.29,76.55,65.72,50.93,72.73,16.13,23.81,52.14,16.05,12.19,71.77,14.97,11.82,33.04,7.86,15.26,72.46,15.42,24.49,15.75,63.78,32.43,36.57,16.24,7.08,26.08,15.74,14.78,16.22,16.85,23.32,31.14,12.72,6.7,26.65,24,12.95,129.92,20.07,11.28,34.66,12.86,17.5,26.5,0.7038,1.22,128.98,23.33,19.2,15.64,8.34,45.01,38.14,50.31,13.11,17.4,47.15,79.29,8.24,28.92,24.97,1.92,77.16,126.5,8.97,3.97,12.85,30.75,37.82,2.36,10.37,52.28,1.56,53,47.33,41.32,10.65,15.24,39.5,94.42,12,54.25,48.03,3.72,6.34,18.5,23.47,26.74,8.74,6.7,7.08,70.92,27.3,65.43,18.776,7.82,16.8,12.0625,124.24,29.79,22.88,29.4,66.44,28.88,1.505,0.8642,10.37,47.14,99.83,133.87,46.41,4.88,57.63,14.45,11.2,34.99,11.06,129.25,7.71,35.2,2.29,2.53,1.65,13.74,15.6,11.84,59.79,33.85,62.48,72.34,25.15,131.2,61.13,2.17,5.1,53.35,26.9,43.15,10.8,63.61,130.91,81.42,45.29,17.58,415.79,118.64,73.88,9.85,79.22,43.39,4.86,32.18,68.36,60.21,34.15,19.47,23.39,29.96,39.58,14.66,5.98,70.87,25.9,38.64,90.45,165.2,46.57,83.18,16.48,134.15,54.68,62.51,12.25,24.33,17.69,60.73,11.51,15.6,85.99,80.81,59.9,17.48,30.73,104.34,0.94,86.03,82.73,14.41,34.05,17.2,11.98,13,52.5,39.2,19.58,101.59,26.38,44.13,18.72,23.3,32.05,27,26.12,13.13,18.58,6.07,73.74,3.53,42.4,12.21,15.72,16.71,26.27,26.69,4.52,35.99,26.1,17.31,45.61,67.9,11.15,13.08,1.1,9.7001,17.51,59.8,26.27,86.95,18.95,26.75,34.33,66.72,107.98,9.7,18.27,24.16,56.8,46.56,91.69,21.43,78.75,3.37,13.71,31.73,100.39,5.65,6.98,85.21,97.84,13.5,26.19,42.43,26.73,10.11,47.95,102.84,66.95,28.35,14.07,5.25,23.68,127.43,11.41,10.43,4.19,25.48,19.78,72.08,53.59,17.41,36.57,92.37,127.48,23.98,16.46,5.28,24.76,9.1,68.33,64.45,8.15,18.54,8.85,119.72,3.62,20.49,2.57,94.05,16.99,25.93,25.12,25.71,9.68,81.26,16.7,77.21,37.45,80.43,6.95,24.95,87.1,20.74,31.82,25.44,25.48,25.5515,46.96,19.11,43.49,10,8.68,16.99,120.79,3.95,1.91,76.54,7.8,33.71,14.59,13.5,15.99,42.6,38.86,46.76,8.1,23.14,23.04,17.39,15.4399,13.62,14,125.94,13.92,22.98,48.68,4.62,68.17,1.14,9.82,29.75,73.66,6.51,92.28,25.53,25.6,25.63,7.59,72.9,25.23,10.41,27.87,10.81,48.76,11.38,3.76,71.78,13.21,53.59,25.55,42.43,68.21,66.25,37.2,6.1,6.24,84.58,13.17,13.2,22.92,82.95,28.9,6.07,74.57,29.35,74.89,64.46,77.91,30.21,11.09,6.34,21.69,56.88,15.25,41.44,1.77,67.42,209.26,11.24,15.8,13.53,15.09,32.8,9.78,12.99,62.77,21.8,39.11,78.68,14.75,10.67,20.6,10.57,36.39,7.24,6.1,13.61,14.58,51.04,20.36,102.48,35.14,12.31,8.98,3.7,81.22,89.67,27.32,13.26,1.54,37.84,11.29,8.98,24.08,4.43,8.54,15.51,36.26,9.33,6.56,43.38,13.04,10.9,54.68,160,164.11,34.25,15.87,14.65,18.72,10.57,13.25,21.08,62.55,6.08,22.72,17.25,14.1,11.91,16.5,17.36,4.93,31.46,75.14,32.84,55.65,21.39,18.76,53.36,52.27,150,11.51,50.35,4.77,16.2,13.83,43.24,94.4,37.89,13.18,35.9,70.65,14.16,11.8273,12.67,22.93,11.11,13.55,9.55,14.24,26.44,13.49,69.92,9.88,157.12,14.93,6.53,13.5,6.83,28.27,13.07,48.33,59,9.67,2.04,28.2,5.82,31.87,65.9,33.14,36.14,30.08,8.49,64.92,4.76,141.98,8.63,10.11,17.27,19.65,30.24,26.53,40.67,26.87,26.25,39.18,1.54,33.93,16.59,7.33,15.36,13.91,1.1,17.12,4.47,15.67,18.68,1.79,15.54,81.13,21.34,27.59,7.46,10.77,503.01,19.74,18.46,15.26,47.57,30.24,6.55,65.34,4.13,13.2,21.55,21.03,29.36,27.27,47.72,10,26.17,7.45,7.62,3.48,18.15,8.2,20.66,97.23,59.46,13.37,7.8,76.6,19.31,9.21,24.18,77.53,0.9,10.8,153.17,23.32,1.18,25.83,42.06,1.48,11.49,24.78,18.24,21.24,6.59,44.54,33.28,64.61,227.17,30,48.14,29.72,45.5,79.45,26.83,4.96,81.03,30.76,72.15,34.48,129.3,65.48,33.48,67.43,34.31,15.05,60.38,32.59,26.84,1.7,32.48,2.31,113.96,1.13,7.3,31.13,12.27,44.48,163.75,4.55,4.93,49.64,7,0.42,4.66,62.44,41.56,21.6,8.18,26.89,33.78,3.79,47.23,27.86,0.5199,45.15,117.21,9.51,74.52,1.8,67.24,22.28,22.735,28.48,13.84,19.61,26.62,25.78,18.95,33.53,21.54,51.22,13.79,34.9,81.22,6.86,15.59,96.42,18.49,31.21,24.57,21.23,22.93,16.32,10.63,11.18,188.35,16.08,18.39,18.17,43.96,62.54,8.82,1.87,33.38,14.9,10.47,16.69,3.2,8.89,3.95,50.02,153.42,7.65,35.53,0.54,18.36,5.24,262.52,4.07,74.98,12.53,13.66,86.82,129.8,24.78,9.8,7.03,21.68,8.1,17.1,7.5,38.4,118.45,6.47,26.92,17.2,7.6,35.32,1.72,25.83,9.11,26.27,13,12.18,12.29,44.75,26.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.3,112.64,26.1,44.12,5.27,8.25,22.99,68.65,75.61,9.07,53.28,10.89,87.69,7.53,5.49,28.77,16.93,31.76,56.22,26.5,25.85,25.7401,6.03,8.52,73.39,17.69,37.86,20.07,20.07,38.7,29.07,148.17,37.66,43.78,7.71,8.06,21.2,15.01,7.65,36.81,27.64,25.07,37.7,41.81,20.87,133.29,56.32,7.4,45.66,1.77,9.84,44.71,111.33,129.74,33.85,83.84,12.96,101.79,60.87,4.87,41.94,27.98,38.29,20.16,3.28,39.63,101.46,18.22,55.85,25.52,26.35,77.89,58.71,106.91,106.8875,82.26,18.76,74.11,14.07,22.74,9.85,32.93,60.84,3.9,14.49,14.35,21.27,1.82,12.3,13.61,54.78,46.51,13.6,9.1,116.12,134.97,14.18,56.62,96.69,3.28,13.6,14.19,47.52,24.93,12.36,27.7,10.77,15.9,66.72,50.39,30.56,4.05,51.47,27.54,37.84,79.17,4.41,34.21,134.96,105.34,35.36,55.08,92.92,69.47039835,24.05,19.76,12.71,60.18,48.91,90.11,26.55,49.2,5.82,2.9,68.28,20.82,40.56,56.32,171.54,11.4,11.94,10.99,11.91,13.69,45.01,10.93,61.78,19.05,9.11,46.67,23.65,66.85,14.14,21.6,30.4,35.89,63.93,10.56,14.96,9.02,29.15,52.18,56.31,29.22,38.54,54.51,133.93,13.7,71.27,2.27,825.61,32.84,56.14,13.07,19.25,17.79,17.89,31.23,69.13,14.81,1.75,115.34,41.85,4.97,33.71,89.67,24.5,27.18,5.98,53.57,9.24,43.24,526.42,3.48,20.92,81.57,5.13,117.44,23.66,12.76,14.3,32.23,12.09,46.25,4.9,5.77,6.24,11.94,8.45,6,38.21,2.05,1.18,1.19,2.17,0.73,3.23,3.05,1.46,2.06,4.68,18.27,0.3199,31.48,2.59,16.44,16.85,16.9,11.91,1.74,122.34,0.82,3.33,0.55,13.02,19.46,2.6,55.43,18.83,28.86,34.75,11.76,10.8,9.5,48.62,12.54,12.8,16.6,16.22,2.9,2.33,16.09,14.56,0.5024,0.24,9.84,0.15,13.19,13.82,14.1466,13.15,13.88,14.07,13.68,14.38,14.85,7.69,0.7663,0.324,1.89,5.35,0.9,0.77,23.7,1.2863,11.39,11.24,6.43,0.97,4.2127,0.3302,2.21,3.5,1.54,0.6,2.65,27.28,2.75,1.78,9.52,2.35,0.11,0.1212,5.68,13.86,31.34,7.6,0.42,1.56,0.6299,12.7,1.05,0.94,2.37,17.12,3.66,0.21,12.61,13.18,1.52,0.3221,0.6634,10.9,63.43,16.37,10.54,16.52,7.5,14.62,5.24,2,3.53,4.53,0.3581,4.75,2.59,0.7299,6.13,0.165,16.42,15.63,9.37,15.04,14.15,10.95,31.46,17.57,6.71,0.525,89.54,0.225,2.27,15.71,2.89,0.84,0.79,30.57,0.2603,8.49,7.26,19.76,44.32,0.6701,2930.11,0.51,2.29,12.6,2.07,0.49,0.5058,1.06,17.75,0.3579,63.51,0.8301,0.75,0.78,0.4875,0.7495,2.52,4.35,0.82,7.66,12.36,12.96,10.735];
I compared matrix x with the 1st and 20th row of c and they are equal:
isequal(x,c([1 20],:))
ans =
1
importdata seems to be working as expected.

read tow Column txt file in specific directory and import to matlab

I have two Column txt file every Column contain the speed on dc motor. I want to plot every Column with the time and compaire the two curves.
I tried this code, but not working:
fid = fopen('C:\Users\Hussam Yonis\Desktop\recive.txt','r');
KK = fscanf(fid,'%f %f',[2,50]);
t=0:0.05:0.05*length(a(:,1))-0.05;
plot(t,fid(:,1),'b',t,fid(:,2),'r')

fid is just a pointer corresponding to the opened file and does not have several dimensions, so fid(:,2) will give a matrix dimensions exceeded error. You want to plot the data that came out of the file, KK in your case. Try this:
plot(t,KK(:,1),'b',t,KK(:,2),'r')
I also suspect you might have your indexing the wrong way round, although as your code is not minimal, complete and verifiable, it is difficult to say. You might find you need the following command:
plot(t,KK(1,:),'b',t,KK(2,:),'r')

Find line tangent of matrix loaded from file

I want to write a script that creates a matrix comprised of two lines with three real numbers on each line (in the range of -1 to 3) and saves it to a file.
I think this can be done by something like:
line(rand(3,2),rand(3,2))
Then I want to write another script that loads the file into a matrix and computes the tangent of every element in the matrix.
How do I solve this problem?

Let's first make random real numbers within the range
I'll make a data variable first
data=(3+1)*rand(2,3)-1;
then save it to the .dat file
save testtan.dat data -ascii
now in two steps I'll simply load it into a matrix and take the tan of every element and store it in mytangents
load testtan.dat
mytangents=tan(load('testtan.dat'))

Getting the format correct when writing data to a text file from a matlab script

I'm trying to write data to a text file from my matlab script. I want two columns which it gives me but I want my time variable (t) followed by my variable (x) which is my amplitude. Its outputting a file like below.
Everything is perfect however i don't believe my (t) variable is first followed by my (x) variable. I'm trying to upload this file to ploy.ly to be graphed but when i set column 1 to my x variable and column 2 to my y variable it plots a oval like below. It's suppose to plot a sinusoidal signal.
My code is as follows:
f = 1E3;
T = 1/f;
tmin = 0;
tmax = 5*T;
dt = T/100;
t = tmin:dt:tmax;
x = sin(2*pi*f*t);
sinData.txt = fopen('sinData.txt','w');
fprintf(sample.txt,'%7.5f,%7.5f\r\n',x);
fclose(sinData.txt);
plot(t,x,'r');
grid on;

MATLAB writes files in column major format. What this means is that it will traverse every row first in one column before moving to the next column. If you have a M x 2 matrix of values where the first column is a vector of t values and the second column is a vector of x values, try transposing the matrix before writing to file. That way, each column represents a pair of (t,x) values for you and MATLAB should be able to preserve writing to the file so that each row is a unique pair.
Also, in your code you are only writing the x values to the file. This makes sense because if you look at your text file going line by line, it pretty much mimics a sinusoidal output. It goes from 0 up to 1, then back to 0 again. Your x vector is a sinusoidal output which thus fits the pattern. As such, you probably want to write the t values as well. To do this, modify the fprintf statement in your code so that it looks like this:
fprintf(sinData.txt,'%7.5f,%7.5f\r\n', [t;x]);
BUG SPOT FROM RTL (Thanks!): Make sure you change sample.txt to sinData.txt in your fprintf statement as that is the name of the handle to the open file that you have opened.
Looking at your code, t and x are row vectors, so this should (hopefully) work. I haven't tried it myself, and I'm somewhere where I don't have MATLAB accessible. Hit me up with a comment and let me know if it works.

IN MATLAB: How to plot a graph every 3 lines from a Text file?

I have a large text file with 2 columns where the values are separated by commas. I am trying to create a simple program which allows to plot a graph with the data extracted for every 3 rows consecutively until reaching the end of the file.
The first 9 rows of my file can be seen below:
115,1.2
324,3.4
987,1.2
435,-2.3
234,1.4
278,1.3
768,3.4
345,-1.3
126,3.6
I have been reading that with 'Textread' I can write my data into multiple outputs and then I can use 'plot', to plot the previous generated outputs on a graph. I know that I will need some loop whiles to repeat the process and indicate the end of the file, etc. But I am struggling to find the way to do this:-(.
I have only managed plotting a graph for the first 3 rows of my file (see code below), but I need this process to be repeated until the end of the file.
[Codes,Values]=textread('MyData.txt','%3u %f',3,'delimiter',',','emptyvalue',NAN); %//Reads the first three rows of my file and stores the values in 2 variables
figure
plot(Codes,Values) %//plots a graph with the variables obtained before
saveas(gcf,'Graph.pdf') %//Saves the created graph in a pdf format file.
I would be very grateful if somebody could help me.

I have finally found out a way. I paste here the code that allows me plotting a graph every three lines from my text file.
[Codes,Values]=textread('MyData.txt','%3u %f','delimiter',',','emptyvalue',NAN); %//Reads my text file and stores the values in 2 variables
nrows=1;
conta=1;
contb=3;
contc=1;
contd=3;
nfig=1;
while nrows<=size(Codes,1)
if contb<=size(Codes,1)
Codes1=Codes(conta:contb,1);
Values1=Values(contc:contd,1);
figure
plot(Codes1,Values1) %//plots a graph with the selected rows.
saveas(gcf,strcat('Graph', num2str(nfig),'.pdf')) %//Saves the created graph in a pdf format file.
else
Codes1=Codes(conta:contb,1);
Values1=Values(contc:contd,1);
figure
plot(Codes1,Values1) %//plots a graph with the selected rows.
saveas(gcf,strcat('Graph', num2str(nfig),'.pdf'))
end
nrows=nrows+3;
conta=conta+3;
contb=contb+3;
contc=contc+3;
contd=contd+3;
nfig=nfig+1;
end

You mentioned that it is a large text file, but will it an issue to load the whole text file and then simply sample every third row, for example, as follows:
[Codes, Values] = textread('MyData.txt','%3u %f','delimiter',',','emptyvalue',NAN);
rowstokeep = 1:3:length(Values) % every third line
plot(Codes{rowstokeep}, Values{rowstokeep}); % plot just the rows you wanted