amol- commented on a change in pull request #12010:
URL: https://github.com/apache/arrow/pull/12010#discussion_r778812702
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File path: python/pyarrow/table.pxi
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@@ -2442,6 +2602,46 @@ def _from_pydict(cls, mapping, schema, metadata):
raise TypeError('Schema must be an instance of pyarrow.Schema')
+def _from_pylist(cls, mapping, schema, metadata):
+ """
+ Construct a Table/RecordBatch from list of dictionary of rows.
+
+ Parameters
+ ----------
+ cls : Class Table/RecordBatch
+ mapping : list of dicts of rows
+ A mapping of strings to row values.
+ schema : Schema, default None
+ If not passed, will be inferred from the Mapping values.
+ metadata : dict or Mapping, default None
+ Optional metadata for the schema (if inferred).
+
+ Returns
+ -------
+ Table/RecordBatch
+ """
+
+ arrays = []
+ if schema is None:
+ names = []
+ if mapping:
+ names = list(mapping[0].keys())
+ for n in names:
+ v = [i[n] if n in i else None for i in mapping]
+ arrays.append(asarray(v))
+ return cls.from_arrays(arrays, names, metadata=metadata)
+ else:
+ if isinstance(schema, Schema):
+ for n in schema.names:
+ v = [i[n] if n in i else None for i in mapping]
+ n_type = schema.types[schema.get_field_index(n)]
+ arrays.append(asarray(v, type=n_type))
Review comment:
Right, my misunderstanding was that we could end up with `v=None`, but
rereading the code block I see that we would actually end up with `v=[None,
None, None]` which is fine.
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