How to access single cell value in Daft way?

[hongbo-miao]

I have a table. name and id column values are unique. Right now I try to get id based on name:

event_name = "abc"
conn_str = "trino://[email protected]/?source=trino-sqlalchemy"
sql_query = f"""
    select cast(id as varchar) as id
    from postgresql.public.my_events
    where name = '{event_name}'
"""
event_df = daft.read_sql(sql_query, conn_str)
collected_df = event_df.collect()
id = collected_df.to_pandas().iloc[0]["id"]

You can see I get string id by id = collected_df.to_pandas().iloc[0]["id"] using pandas.
However, I hope to avoid pandas.
Is there a Daft way to get it? Thanks! 😃

[universalmind303]

I think the most efficient way would be to use to_arrow and extract the cell that way

df = daft.from_pydict({"id": [1,2,3]});
df.to_arrow()["id"][1].as_py() # 2

you can also use to_pydict or to_pylist depending on if you want columnar (pydict) or row (pylist). pydict will be faster as it's closer to our in memory representation

df.to_pydict()['id'][1] # 2
df.to_pylist()[1]['id'] # 2