How to select first 3 distinct values in a column

Question

I am trying to select the first 3 distinct points in a column excluding the first 0 point. I need distinct points to perform polynomial regression.

My_column:

  A = np.array([0, 0.5, 0, 0 ,1.0, 2.0])

Expected:

  B = np.array([0, 0.5, 0.0, 1.0])

Essentially I want to skip over one 0 and select the 1.0 instead.

What have you tried so far? Demonstrate this with code and highlight the exact problem you have. — sophros, Jul 16 '19 at 08:40
Possible duplicate of [Getting first n unique elements from Python list](https://stackoverflow.com/questions/53887803/getting-first-n-unique-elements-from-python-list) — sophros, Jul 16 '19 at 08:41
@sophros i tried to manually do an if statement to check if the previous number at location [i] == to the current number at location [i+1]. But i am unable to select it and i am not sure how to move on from here. — Ng Jian Sheng, Jul 16 '19 at 08:57

score 0 · Answer 1 · edited Jul 16 '19 at 09:01

0

import numpy as np

A = np.array([0, 0.5, 0, 0 ,1.0, 2.0])
B = A[0]
B = np.append(B, list(set(A[1:]))[:3])
print(B)

edited Jul 16 '19 at 09:01

Sraw

answered Jul 16 '19 at 08:44

Piyush Sinha

thanks! but i am having an error. TypeError: unhashable type: 'numpy.ndarray' – Ng Jian Sheng Jul 16 '19 at 08:51
`set` does not maintain the order of elements from `A`. It seems to me that your solution does not answer the OT's question. – sophros Jul 16 '19 at 11:58

1 Answers1