DarthLazar DarthLazar - 4 months ago 16
Python Question

Creating an array for distance between two 3-D arrays

So I have two arrays that have x, y, z coordinates. I'm just trying to apply the 3D distance formula. Problem is, that I can't find a post that constitutes arrays with multiple values in each column and spits out an array.

print MW_FirstsubPos1

[[ 51618.7265625 106197.7578125 69647.6484375 ]
[ 33864.1953125 11757.29882812 11849.90332031]
[ 12750.09863281 58954.91015625 38067.0859375 ]
...,
[ 99002.6640625 96021.0546875 18798.44726562]
[ 27180.83984375 74350.421875 78075.78125 ]
[ 19297.88476562 82161.140625 1204.53503418]]

print MW_SecondsubPos1

[[ 51850.9140625 106004.0078125 69536.5234375 ]
[ 33989.9375 11847.11425781 12255.80859375]
[ 12526.203125 58372.3046875 37641.34765625]
...,
[ 98823.2734375 95837.1796875 18758.7734375 ]
[ 27047.19140625 74242.859375 78166.703125 ]
[ 19353.97851562 82375.8515625 1147.07556152]]


Yes, they are the same shape.

My attempt,

import numpy as np

xs1,ys1,zs1 = zip(*MW_FirstsubPos1)
xs11,ys11,zs11 = zip(*MW_SecondsubPos1)

squared_dist1 = (xs11 - xs1)**2 + (ys11 - ys1)**2 + (zs11 - zs1)**2
dist1 = np.sqrt(squared_dist1)

print dist1


This returns:

TypeError: unsupported operand type(s) for -: 'tuple' and 'tuple'


I'm just wanting to return a 1-D array of the same shape.

Answer

See if this works, assuming that aaa and bbb are normal python list of lists having the x, y and z coordinates (or that you can convert to such, using tolist or something like that perhaps). result will have the 1-D array you are looking for.

result = []
for a, b in zip(aaa, bbb):
    dist = 0
    for i in range(3):
        dist += (a[i]-b[i])**2
    result.append(dist**0.5)