Removing Rows In A 2D Array That Have The Same Value

I'm looking for a quick way to remove duplicate values present in a 2D array on a first come first serve basis. I know a way to remove the rows if they are identical, but not if on

Solution 1:

A pure-Python way will be to use set with a list-comprehension:

>>> seen = set()
>>> np.array([x for x in a if seen.isdisjoint(x) and not seen.update(x)])
array([[0, 1],
       [3, 4],
       [2, 5]])

The one-liner simply abuses the fact that set.update returns None, so when seen.isdisjoint(x) is True we can update the seen set using not seen.update(x).

We can also write the above code as:

seen = set()
out = []
for item in a:
    # if none of items in current sub-array are present in seen set
    # then add current sub-array to our list. Plus update the seen
    # set with the items from current sub-array
    if seen.isdisjoint(item):
        out.append(item)
        seen.update(item)
...         
>>> out
[array([0, 1]), array([3, 4]), array([2, 5])]
>>> np.array(out)
array([[0, 1],
       [3, 4],
       [2, 5]])