# Loop Question for particle

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shah nawaz on 13 May 2020
Answered: Reshma Nerella on 24 Jul 2020
I have following data I want to use first 2 columns in a for loop to detect the particles for which there is no contact. first 2 columns show 2 particles which are in contact. How can I get an output in tabular form. Basically i want to detect those particles for which there is no contact. Particles are 484 and total number of contacts is 956.
1 324 0.720141865396207E+00 0.000000000000000E+00 0 0.000000000000000E+00
1 439 0.940050831127248E+00 0.000000000000000E+00 0 0.000000000000000E+00
1 441 0.131609998985588E+01 0.000000000000000E+00 0 0.000000000000000E+00
2 25 0.363379567116406E+00 -0.000000000000000E+00 0 0.000000000000000E+00
2 89 0.753090369602638E+00 0.000000000000000E+00 0 0.000000000000000E+00
2 109 0.851303474754872E+00 0.000000000000000E+00 0 0.000000000000000E+00
2 220 0.898508917122121E+00 -0.000000000000000E+00 0 0.000000000000000E+00
3 6 0.890341369366110E+00 0.000000000000000E+00 0 0.000000000000000E+00
3 26 0.283864328102457E+00 0.000000000000000E+00 0 0.000000000000000E+00
Data = importdata('dem22.txt');
Particle1 = Data(:,1);
Particle2 = Data(:,2);
number_of_particles = 484
total_contacts = length(Particle1);
Contact = Particle1+Particle2
Table = cell(956,2);
for i = 1:1:ncont;
j = 1:npa;
Contact(ncont,1) = i;
i = i+1;
Contact(ncont,2) = j;
j=j+1;
Table(i,:) = {i j};
fprintf('%d %d\n', Table{i,:});
end
T = table(Contact,npa);

Show 1 older comment
shah nawaz on 14 May 2020
I want to show no contact as zero in the form of a table. Sorry first 2 columns show 2 particles which are in contact not the contact numbers.
Geoff Hayes on 14 May 2020
I still don't understand how you determine "no contact" particles. Can you illustrate with an example?
shah nawaz on 14 May 2020
I want to determine those particles which are not in column1 and columns2 and count them. total particles 484

Reshma Nerella on 24 Jul 2020
Hi,
You can use union and setdiff functions to find out the particles that are not in contact.
Total_Particles - all particles
Particle1 - particles in column 1
Particle2 - particles in column 2
Contacted_Particles=union(Particle1, Particle2 ) - all particles that are in contact
setdiff(Total_Particles,Contacted_Particles) - gives particles that are not in contact.
Total_Particles, Particle1, Particle2 are all arrays with particle numbers