The following is Claude’s LLM answer to your query - hope it helps you!

Here’s how you can handle this:

1. When loading the CSV, you can use the parse_dates option to automatically parse date/datetime strings:

df = Explorer.DataFrame.from_csv!("your_file.csv", parse_dates: true)

If that doesn’t work automatically, you can manually convert the column using mutate. Here’s how:

require Explorer.DataFrame

df = Explorer.DataFrame.mutate(
  df,
  datetime_col: cast(string_datetime_col, :datetime)
)

For more control over the parsing, you can use Explorer’s datetime casting functions. Here’s a complete example:

require Explorer.DataFrame, as: DF

# Starting with your string datetime column
df = DF.from_csv!("your_file.csv")

# Convert string to datetime
df = DF.mutate(
  df,
  datetime_col: strptime(string_datetime_col, "%Y-%m-%d %H:%M:%S", unit: :microsecond)
)

# If you specifically need just the date portion:
df = DF.mutate(
  df,
  date_col: dt_date(datetime_col)
)

For a more streamlined workflow from Ecto to Explorer, consider:

1. Use Ecto’s select_merge to format dates in the query itself
2. Or use Explorer’s ADBC functionality to read directly from your database:

{:ok, df} = Explorer.DataFrame.from_query(
  conn,  # ADBC connection
  "SELECT * FROM your_table",
  []
)

This would give you properly typed columns directly from your database without needing the CSV intermediate step.

The key functions to remember for datetime manipulation in Explorer are:

• strptime - Parse string to datetime
• cast - General type conversion
• dt_date - Extract date from datetime
• parse_dates option in from_csv