I have a polars dataframe df which has a datetime column date. I'm trying to get the name of the day and month of that column. Consider the following example. import polars as pl from datetime import datetime df = pl.DataFrame({ "date": [datetime(2024, 10, 1), datetime(2024, 11, 2)] })  I was hoping that I could pass parameter to month() or weekday() to get the desired format. df.with_columns( pl.col("date").dt.month().alias("Month"), pl.col("date").dt.weekday().alias("Day") )  shape: (2, 3) ┌─────────────────────┬───────┬─────┐ │ date ┆ Month ┆ Day │ │ --- ┆ --- ┆ --- │ │ datetime[μs] ┆ i8 ┆ i8 │ ╞═════════════════════╪═══════╪═════╡ │ 2024-10-01 00:00:00 ┆ 10 ┆ 2 │ │ 2024-11-02 00:00:00 ┆ 11 ┆ 6 │ └─────────────────────┴───────┴─────┘  However, this does not seem to be the case. My desired output looks as follows. shape: (2, 3) ┌─────────────────────┬───────┬──────────┐ │ date ┆ Month ┆ Day │ │ --- ┆ --- ┆ --- │ │ datetime[μs] ┆ str ┆ str │ ╞═════════════════════╪═══════╪══════════╡ │ 2024-10-01 00:00:00 ┆ Oct ┆ Tuesday │ │ 2024-11-02 00:00:00 ┆ Nov ┆ Saturday │ └─────────────────────┴───────┴──────────┘  How can I extract the day and month name from the date column?
You can use pl.Expr.dt.strftime to convert a date / time / datetime column into a string column of a given format. The format can be specified using the chrono strftime format. In your specific example, the following specifiers might be of interest:  %B for the full month name. %b for the abbreviated month name. Always 3 letters. %A for the full weekday name. %a for the abbreviated weekday name. Always 3 letters.  df.with_columns( pl.col("date").dt.strftime("%B").alias("month"), pl.col("date").dt.strftime("%b").alias("month (short)"), pl.col("date").dt.strftime("%A").alias("day"), pl.col("date").dt.strftime("%a").alias("day (short)"), )  shape: (2, 5) ┌─────────────────────┬──────────┬───────────────┬──────────┬─────────────┐ │ date ┆ month ┆ month (short) ┆ day ┆ day (short) │ │ --- ┆ --- ┆ --- ┆ --- ┆ --- │ │ datetime[μs] ┆ str ┆ str ┆ str ┆ str │ ╞═════════════════════╪══════════╪═══════════════╪══════════╪═════════════╡ │ 2024-10-01 00:00:00 ┆ October ┆ Oct ┆ Tuesday ┆ Tue │ │ 2024-11-02 00:00:00 ┆ November ┆ Nov ┆ Saturday ┆ Sat │ └─────────────────────┴──────────┴───────────────┴──────────┴─────────────┘ 