combine arrays if duplicate element is found in another array python

Question

I have a list of arrays that go like:

[array(['A2', 'A1'], dtype=object),
 array(['A2', 'A3'], dtype=object),
 array(['A2', 'A4'], dtype=object),
 array(['A1', 'A3'], dtype=object),
 array(['A1', 'A4'], dtype=object),
 array(['A3', 'A4'], dtype=object),
 array(['B2', 'B1'], dtype=object),
 array(['B2', 'B3'], dtype=object),
 array(['B1', 'B3'], dtype=object)]

I want to combine those arrays if one of the elements in an array is found in another array. And then remove the duplicate.

The expected outcome should go like:

[array['A1', 'A2', 'A3', 'A4'], array[B1', 'B2', 'B3']]

Any idea about how I can do this? Cheers!

Alex Hall · Accepted Answer · 2020-07-25 10:05:22Z

1

It sounds like you want the connected components of a graph.

from numpy import array

edges = [
    array(['A2', 'A1'], dtype=object),
    array(['A2', 'A3'], dtype=object),
    array(['A2', 'A4'], dtype=object),
    array(['A1', 'A3'], dtype=object),
    array(['A1', 'A4'], dtype=object),
    array(['A3', 'A4'], dtype=object),
    array(['B2', 'B1'], dtype=object),
    array(['B2', 'B3'], dtype=object),
    array(['B1', 'B3'], dtype=object),
]

import networkx
G = networkx.Graph()
G.add_edges_from(edges)
print(list(networkx.connected_components(G)))
# [{'A1', 'A3', 'A4', 'A2'}, {'B2', 'B1', 'B3'}]

Demo: https://repl.it/repls/FluidPleasedScope

networkx documentation

answered Jul 25, 2020 at 10:05

Alex Hall

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Comments

sushanth · Accepted Answer · 2020-07-25 10:28:00Z

0

You can use, np.unique + itertools.groupby

from itertools import groupby
from numpy import array, unique

values = [
    array(['A2', 'A1'], dtype=object),
    array(['A2', 'A3'], dtype=object),
    array(['A2', 'A4'], dtype=object),
    array(['A1', 'A3'], dtype=object),
    array(['A1', 'A4'], dtype=object),
    array(['A3', 'A4'], dtype=object),
    array(['B2', 'B1'], dtype=object),
    array(['B2', 'B3'], dtype=object),
    array(['B1', 'B3'], dtype=object)
]

print([
    list(v) for _, v in groupby(unique(values), key=lambda x: x[0])
])

[['A1', 'A2', 'A3', 'A4'], ['B1', 'B2', 'B3']]

edited Jul 25, 2020 at 10:28

answered Jul 25, 2020 at 10:10

sushanth

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