如何在numpy数组中找到唯一的对象?

help 属于 numpy.unique 说

unique(ar, return_index=False, return_inverse=False, return_counts=False, axis=None)
    Find the unique elements of an array.
    
    Returns the sorted unique elements of an array. There are three optional
    outputs in addition to the unique elements:
    
    * the indices of the input array that give the unique values
    * the indices of the unique array that reconstruct the input array
    * the number of times each unique value comes up in the input array
    
    Parameters
    ----------
    ar : array_like
        Input array. Unless `axis` is specified, this will be flattened if it
        is not already 1-D.

因此,它失败了,因为你的一个对象没有 __lt__ 排序所需的方法,若您只想找到唯一的,但顺序与您可能做的无关

import collections
import numpy as np
v = np.array(["abc",None,1,2,3,"3",2])
cnt = collections.Counter(v.ravel())
uniq = [k for k,v in cnt.items() if v==1]
print(uniq)

输出:

['abc', None, 1, 3, '3']

一种方法是定义 __lt__ 对于数组中的所有对象。另一种不需要排序并且只依赖于等式运算符(仅适用于可清洗对象)的更简单的方法是在python中使用set:

np.array(list(set(v)))

输出:

array([1, 2, 3, None, '3', 'abc'], dtype=object)