Hi I tried the new python labs node and have an issue when writing back import knime_io as knio import pyarrow as pa # This example script simply outputs the node's input table. print(type(knio.input_tables[0])) df = knio.input_tables[0].to_pandas() print(df.head()) df = df[['Cat','CustomerID']] ar = pa.Table.from_pandas(df) #does not work knio.output_tables[0] = knio.write_table(ar) #does work #knio.output_tables[0] = knio.write_table(knio.input_tables[0]) In the Node both work but when I close the node and execute the workflow the upper throws me an error Any ideas? It just tells me exception occurred in the python kernel. Thanks

Hi @Daniel_Weikert , could you try to run knio.output_tables[0] = knio.write_table(df) instead of ar = pa.Table.from_pandas(df) knio.output_tables[0] = knio.write_table(ar) and see if that works? KNIME performs some additional type handling when converting between Pandas and PyArrow internally, but when you do it manually KNIME cannot do that for you. So that could be the culprit. A minimal workflow using the same data types (but maybe randomized data) as your real workflow would help us to reproduce and understand the problem better. Best, Carsten

Python Knio write error

KNIME Analytics Platform

mlauber71 July 23, 2022, 8:31am 4

@Daniel_Weikert oils you check your python setup and maybe try with a fresh one following the KNIME Python Guide or the provided yaml files.

Logs in debug modus:

Also you might create a minimal workflow that could be checked.