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POWhen I access a list on an object it incorrectly returns as empty list
 

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  1. POWhen I access a list on an object it incorrectly returns as empty list
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    <p>I am writing a code for a computational physics project.</p> <p>I'd like to know how I can implement a class in python by adding an array to the instances of the class.</p> <p>Here is my original part of code:</p> <pre><code>class Particle(): def __init__(self, (x,y,z), n, radius, neighbours): self.n = n self.x = x self.y = y self.z = z self.radius = radius number = loadtxt("final_limited.txt", usecols=(0,), unpack=True, dtype = int) c1,c2,c3,r = loadtxt("final_limited.txt", usecols=(1,2,3,5), unpack=True, dtype=float) number_of_particles = len(number) my_particles = [] overlap = [] contact_number = [] for i in range(number_of_particles): n = number[i] x = c1[i] y = c2[i] z = c3[i] radius = r[i] neighbours = [] particle = Particle((x,y,z), n, radius, neighbours) my_particles.append(particle) for particle1 in my_particles: count = 0 for particle2 in my_particles: distance = PBCdist(particle1, particle2) sum_of_radii = Sum_radii(particle1, particle2) if (distance &lt; sum_of_radii) and (distance&gt;0): count +=1 olap = (Decimal(sum_of_radii) - Decimal(distance)) overlap.append(olap) contact_number.append(count) </code></pre> <p>I would like to do the following:</p> <pre><code>class Particle(): def __init__(self, (x,y,z), n, radius, neighbours): neighbours = [] self.n = n self.x = x self.y = y self.z = z self.radius = radius self.neighbours = neighbours </code></pre> <p>And then, in the nested loop:</p> <pre><code>for particle1 in my_particles: count = 0 for particle2 in my_particles: distance = PBCdist(particle1, particle2) sum_of_radii = Sum_radii(particle1, particle2) if (distance &lt; sum_of_radii) and (distance&gt;0): count +=1 neighbours.append(particle2.n) olap = (Decimal(sum_of_radii) - Decimal(distance)) overlap.append(olap) contact_number.append(count) </code></pre> <p>As you can see, I'd like to give associate to each particle the list of its neighbours as a property of each element of the class.</p> <p>However, when I check it this code does not work. I'd like tp be able to say type:</p> <pre><code>print my_particles[0].neighbours </code></pre> <p>And obtain the list.</p> <p>Moreover, do you know if there is a Numpy dtype like float that can give me the required 20-21 decimal places? Using float data type my code is of course faster(10 times), but i'd like to use a numpy type that allows full precision required, rather than Decimal.</p>
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    1. USLennart Regebro
    1. USBlaise Delaney
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      1. POWhen I access a list on an object it incorrectly returns as empty list
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