Edit matrix with condition

I have a large matrix of position & velocities of multiple particles:

I need to create a similar new matrix with a condition on radial location (column 7)

for example:

If my particle radial location (column 7) is beween 0.0100 to 0.0115, create a new matrix with corresponding position & vecloties (column 1,2,3&4).

X Y Vx Vy Frame Particle RadialLocation

I have tried but it is very slow!

my matrix size is large ~ (4200000 * 7)

            if (mm(j,7) <= 0.0115) && (mm(j,7) > 0.0100)               
                p_n(j,1) = mm(j,1);
                p_n(j,2) = mm(j,2);
                v_n(j,1) = mm(j,3);
                v_n(j,2) = mm(j,4);
            else 
                p_b(j,1) = mm(j,1);
                p_b(j,2) = mm(j,2);
                v_b(j,1) = mm(j,3);
                v_b(j,2) = mm(j,4);
            end   

[Torsten]

Using the same index j for the position in your new matrix as in your original matrix should be wrong.

Answer 1

[Voss]

idx = mm(:,7) <= 0.0115 & mm(:,7) > 0.01;

p_n = mm(idx,1:2);
v_n = mm(idx,3:4);

p_b = mm(~idx,1:2);
v_b = mm(~idx,3:4);