multiple text files into one in a for loop

Hi,

I am trying to join multiple text files into one. RIght now, in my code, I have IT number of datafiles but I would like to all combine into one with the rows following on from the previous iteration. The file needs to contain all the columns of data that are shown in the table P to store large amounts of data. Here is my code:

If anyone can help it would be greatly appreciated.

for IT = 1:50
    x1 = -15+30*rand(3,1);
    x2 = -15+30*rand(3,1);
    
N = 2;

r_t = 7000*1000;   %km
g_t = 9.8;    %m/s2
r = r_t;
g = g_t;

tau_d = 300;
t = 1;
omega = sqrt(g/r);

% target positions

e1 = [1; 1; 0];
e2 = [0; 0; -1];

%parameters and unknowns
mu = 398600.5;
n = sqrt(mu/r_t^3);
b = 0.112;
k1 = 1;
d = 0.037;
k2 = 1;
norm_d = norm(e1-e2);
c = -d/norm_d * exp(-norm_d^2/k2) - b/norm_d*exp(-norm_d^2/k1);
lambda = [b, c, d, k1, k2];

v1_gf = gf_sat_1_vel2(x1, x2, e1, e2, lambda, omega, tau_d, t, N);

v2_gf = gf_sat_1_vel2(x1, x2, e1, e2, lambda, omega, tau_d, t, N);

v10 = [0; 0; 0];

v20 = [0; 0; 0];

y0 = [x1(1); x1(2); x1(3); v10(1); v10(2); v10(3); x2(1); x2(2); x2(3); v20(1); v20(2); v20(3)];
dt=1;
tspan = 0:dt:1000;

[t,y] = ode45(@(t,y)ClohesseyWiltshire(y, n, lambda, e1, e2, omega, tau_d, t, N),tspan, y0);
U1 = zeros(length(t),length(e1));
U2 = zeros(length(t),length(e2));
dv1 = 0;
dv2 = 0;
for i = 1 : length(t)
    [u1, u2, vg1, vg2] = ClohesseyWiltshire_u(y(i,:), n, lambda, e1, e2, omega, tau_d, t(i), N);
    U1(i, :) = u1;
    U2(i, :) = u2;
    VD1(i, :) = vg1;
    VD2(i, :) = vg2;
    
    U1_norm(i) = norm(u1);
    U2_norm(i) = norm(u2);
    
    v1_gf = gf_sat_1_vel2(x1, x2, e1, e2, lambda, omega, tau_d, t(i), N);
    V1GF(i, :) = v1_gf;
    
    v2_gf = gf_sat_2_vel2(x1, x2, e1, e2, lambda, omega, tau_d, t(i), N);
    V2GF(i, :) = v2_gf;
    
    
   if i ~= 1
   dv1 = norm(u1) * (t(i) - t(i-1)) + dv1;
   dv2 = norm(u2) * (t(i) - t(i-1)) + dv2;
   end

end

R1 = y(:,1:3);
R1 = R1';
V1 = y(:,4:6);
V1 = V1';
R2 = y(:,7:9);
R2 = R2';
V2 = y(:,10:12);
V2 = V2';

title('Trajectories of Two Satellite Configuration - Gravitational Field')
xlabel('X')
ylabel('Y')
zlabel('Z')
legend({'Satellite 1','Satellite 2'},'Location','Southwest')


V1 = V1';
V2 = V2';
R1 = R1';
R2 = R2';
U1_norm = U1_norm';
U2_norm = U2_norm';
tspan = tspan';

% Create columns of data
% Create a table with the data and variable names
P = table(t, U1, VD1, U2, VD2, V1, V2, R1, R2, V1GF, V2GF, 'VariableNames', {'t', 'U1', 'VD1', 'U2', 'VD2' 'V1', 'V2', 'R1', 'R2', 'V1GF', 'V2GF'});
% Write data to text file
name = ['Database2/',num2str(IT), 'Database.txt'];
writetable(P, name)
end 

[Rik]

Isn't it easiest to merge the table? Or to read the tables from the files after this loop has written all (temporary) files?

[Chris Murchison]

Thanks for the reply, how would I do this?

[Rik]

I never work with tables, so I would have to do the same thing as you: either look through the documentation, or try [P1;P2], or see if it is easier to read the files and merge the text output.

Answer 1

[Divya Gaddipati]

Initialize a table before the loop

You can combine two tables inside the loop in the following way:

T = table(); % Create table with the required variable names
for i=1:IT
    % Create table inside the loop to append to the original
    Tnew = table();
    T = [T; Tnew];
end