如何在Python 2D数组中实现set()函数？

def set_2d_array(arr):
    return list(set([item for sublist in arr for item in sublist]))

# 示例
arr = [[1, 2, 3], [2, 3, 4], [5, 6, 7]]
print(set_2d_array(arr))  # 输出：[1, 2, 3, 4, 5, 6, 7]

def set_2d_array(arr):
    return list({item: None for sublist in arr for item in sublist}.keys())

# 示例
arr = [[1, 2, 3], [2, 3, 4], [5, 6, 7]]
print(set_2d_array(arr))  # 输出：[1, 2, 3, 4, 5, 6, 7]

import numpy as np

def set_2d_array(arr):
    return np.unique(np.concatenate(arr)).tolist()

# 示例
arr = [[1, 2, 3], [2, 3, 4], [5, 6, 7]]
print(set_2d_array(arr))  # 输出：[1, 2, 3, 4, 5, 6, 7]