尝试：

# sort the array by the last column
orders = np.argsort(arr[:,-1])

# rearrange the array increasingly by last column
arr = arr[orders]

# use `unique` to find the unique pairs
# `return_index` option returns the indexes of the first occurrence for each pair
# since last column is increasing, first instance means minimum value
uniques, indexes = np.unique(arr[:,:-1], axis=0, return_index=True)

# extract the first instances together with the last column
out = arr[indexes]

示例数据：

np.random.seed(1)
arr = np.random.randint(0,2, (10,3))
arr[:,-1] = np.random.randint(0,5,10)

输出：

array([[0, 0, 1],
       [0, 1, 0],
       [1, 0, 1],
       [1, 1, 1]])