Remove duplicate coordinates stored in arrays in python

Question

I am storing 3d coordinates in three arrays. Below follows an example of a total of four entries of coordinate points, of the coordinates (1,2,3), (2,3,4) and (3,4,5), where the first coordinate point is duplicated.

x = [1, 2, 3, 1]
y = [2, 3, 4, 2]
z = [3, 4, 5, 3]

Now, I would like to as efficiently as possible remove duplicate coordinates, such that the above arrays result in

x_prime = [1, 2, 3]
y_prime = [2, 3, 4]
z_prime = [3, 4, 5]

...still containing the same coordinates (1,2,3), (2,3,4) and (3,4,5) however with no duplicate entry of (1,2,3)

tomtomfox · Accepted Answer · 2021-06-28 15:28:29Z

2

In pure python:

x_prime = list(dict([e, 0] for e in x).keys())

EDIT:

Mustafa Aydin's solution in the comments is even simpler :

list(dict.fromkeys(x))

edited Jun 28, 2021 at 15:28

answered Jun 27, 2021 at 18:21

tomtomfox

2891 silver badge7 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Mustafa Aydın Over a year ago

you can also use list(dict.fromkeys(x)) for your order preserving solution.

akuiper · Accepted Answer · 2021-06-27 18:18:30Z

1

You can use np.unique(..., axis=0):

np.unique(np.array([x, y, z]).T, axis=0)
# [[1 2 3]
#  [2 3 4]
#  [3 4 5]]

If you need to unpack the result:

x_prime, y_prime, z_prime = np.unique(np.array([x, y, z]).T, axis=0)

x_prime
# [1 2 3]

y_prime
# [2 3 4]

z_prime
# [3 4 5]

answered Jun 27, 2021 at 18:18

akuiper

216k33 gold badges362 silver badges379 bronze badges

Comments

Sawradip Saha · Accepted Answer · 2021-06-27 18:32:19Z

1

I guess this is a simple, pythonic and linear solution of your problem. Please let me know the performance.

l = []
for a, b, c in zip(x, y, z):
    l.append((a, b, c))

x_prime = []
y_prime = []
z_prime = []

for a, b, c in set(l):
    x_prime.append(a)
    y_prime.append(b)
    z_prime.append(c)

answered Jun 27, 2021 at 18:32

Sawradip Saha

1,5111 gold badge14 silver badges15 bronze badges

Collectives™ on Stack Overflow

Remove duplicate coordinates stored in arrays in python

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related