Describe the bug, including details regarding any error messages, version, and platform.
Describe the enhancement requested
in R there is concat_tables(..., unify_schemas = TRUE)(https://arrow.apache.org/docs/r/reference/concat_tables.html)
In python this function does not allow concat table with different schema.
unify_schemas
If TRUE, the schemas of the tables will be first unified with fields of the same name being merged, then each table will be promoted to the unified schema before being concatenated. Otherwise, all tables should have the same schema.
I tried the promote_options="permissive" which does not seem to do the trick.
t1 = pa.Table.from_pydict({'a': [1., 2], 'b': [{'k1': 0, 'k2':1}, {'k3': 'ok'}]})
t2 = pa.Table.from_pydict({'a': [1., None], 'b': [{'k1': None}, {'k3': None}]})
pa.concat_tables([t1, t2], unify_schemas=True, promote_options="permissive")
It will have ArrowTypeError: struct fields don't match or are in the wrong order: Input fields: struct<k1: null, k3: null> output fields: struct<k1: int64, k2: int64, k3: string>
I expect this will be just ok
cdef cppclass CConcatenateTablesOptions" arrow::ConcatenateTablesOptions":
c_bool unify_schemas
CField.CMergeOptions field_merge_options
We can see the bool field is already defined in there, but there is no way to set value in the actual function
| defconcat_tables(tables, MemoryPool memory_pool=None, str promote_options="none", **kwargs): |
in the code you only set the field_merge_options which is option of unify_schema().
I think you either should initialize the unify_schemas to true, oh you need to actually handle the keyword unify_schemas. Otherwise, the field merge options actually not in effect at all.
Component(s)
Parquet, Python
Describe the bug, including details regarding any error messages, version, and platform.
Describe the enhancement requested
in R there is
concat_tables(..., unify_schemas = TRUE)(https://arrow.apache.org/docs/r/reference/concat_tables.html)In python this function does not allow concat table with different schema.
I tried the promote_options="permissive" which does not seem to do the trick.
It will have
ArrowTypeError: struct fields don't match or are in the wrong order: Input fields: struct<k1: null, k3: null> output fields: struct<k1: int64, k2: int64, k3: string>I expect this will be just ok
We can see the bool field is already defined in there, but there is no way to set value in the actual function
arrow/python/pyarrow/table.pxi
Line 5169 in f98a132
in the code you only set the field_merge_options which is option of unify_schema().
I think you either should initialize the unify_schemas to true, oh you need to actually handle the keyword unify_schemas. Otherwise, the field merge options actually not in effect at all.
Component(s)
Parquet, Python