Variable-length Attributes in Python

haehn · July 31, 2019, 12:11am

Hello - I am new to TileDB but I am starting to enjoy it

When will Variable-length Attributes be available in the Python API?

ihnorton · July 31, 2019, 2:27am

Variable-length attributes are available – I will update that doc. Object arrays (np.dtype("O") / np.object) can contain variable-length subarrays as elements. If something doesn’t work the way you hope, please let us know here or on github. There are a number of examples in the following test section:

github.com

TileDB-Inc/TileDB-Py/blob/dev/tiledb/tests/test_libtiledb.py#L1083-L1274


class DenseVarlen(DiskTestCase):
    def test_varlen_write_bytes(self):
        A = np.array(['aa','bbb','ccccc','ddddddddddddddddddddd','ee','ffffff','g','hhhhhhhhhh'], dtype=bytes)


        # basic write
        ctx = tiledb.Ctx()
        dom = tiledb.Domain(tiledb.Dim(ctx=ctx, domain=(1, len(A)), tile=len(A)), ctx=ctx)
        att = tiledb.Attr(dtype=np.bytes_, ctx=ctx)


        schema = tiledb.ArraySchema(dom, (att,), ctx=ctx)


        tiledb.DenseArray.create(self.path("foo"), schema)
        with tiledb.DenseArray(self.path("foo"), mode='w', ctx=ctx) as T:
            T[:] = A


        with tiledb.DenseArray(self.path("foo"), mode='r', ctx=ctx) as T:
            assert_array_equal(A[:], T[:])




    def test_varlen_write_unicode(self):

This file has been truncated. show original

(btw, NumPy tries very hard to keep arrays contiguous, so it can sometimes be tricky to maintain the object dtype when operating on an array)

haehn · August 1, 2019, 11:11am

Thank you so much! Will try it!

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Variable-length Attributes in Python

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