from __future__ import annotations from typing import TYPE_CHECKING from typing import Generic from typing import TypeVar if TYPE_CHECKING: from typing_extensions import Self from narwhals.expr import Expr from narwhals.typing import TimeUnit ExprT = TypeVar("ExprT", bound="Expr") class ExprDateTimeNamespace(Generic[ExprT]): def __init__(self: Self, expr: ExprT) -> None: self._expr = expr def date(self: Self) -> ExprT: """Extract the date from underlying DateTime representation. Returns: A new expression. Raises: NotImplementedError: If pandas default backend is being used. Examples: >>> from datetime import datetime >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "a": [datetime(2012, 1, 7, 10, 20), datetime(2023, 3, 10, 11, 32)] ... } >>> df_pd = pd.DataFrame(data).convert_dtypes(dtype_backend="pyarrow") >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a library agnostic function: >>> def agnostic_dt_date(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.select(nw.col("a").dt.date()).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_date`: >>> agnostic_dt_date(df_pd) a 0 2012-01-07 1 2023-03-10 >>> agnostic_dt_date(df_pl) shape: (2, 1) ┌────────────┐ │ a │ │ --- │ │ date │ ╞════════════╡ │ 2012-01-07 │ │ 2023-03-10 │ └────────────┘ >>> agnostic_dt_date(df_pa) pyarrow.Table a: date32[day] ---- a: [[2012-01-07,2023-03-10]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.date(), self._expr._metadata ) def year(self: Self) -> ExprT: """Extract year from underlying DateTime representation. Returns the year number in the calendar date. Returns: A new expression. Examples: >>> from datetime import datetime >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "datetime": [ ... datetime(1978, 6, 1), ... datetime(2024, 12, 13), ... datetime(2065, 1, 1), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_year(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... nw.col("datetime").dt.year().alias("year") ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_year`: >>> agnostic_dt_year(df_pd) datetime year 0 1978-06-01 1978 1 2024-12-13 2024 2 2065-01-01 2065 >>> agnostic_dt_year(df_pl) shape: (3, 2) ┌─────────────────────┬──────┐ │ datetime ┆ year │ │ --- ┆ --- │ │ datetime[μs] ┆ i32 │ ╞═════════════════════╪══════╡ │ 1978-06-01 00:00:00 ┆ 1978 │ │ 2024-12-13 00:00:00 ┆ 2024 │ │ 2065-01-01 00:00:00 ┆ 2065 │ └─────────────────────┴──────┘ >>> agnostic_dt_year(df_pa) pyarrow.Table datetime: timestamp[us] year: int64 ---- datetime: [[1978-06-01 00:00:00.000000,2024-12-13 00:00:00.000000,2065-01-01 00:00:00.000000]] year: [[1978,2024,2065]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.year(), self._expr._metadata ) def month(self: Self) -> ExprT: """Extract month from underlying DateTime representation. Returns the month number starting from 1. The return value ranges from 1 to 12. Returns: A new expression. Examples: >>> from datetime import datetime >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "datetime": [ ... datetime(1978, 6, 1), ... datetime(2024, 12, 13), ... datetime(2065, 1, 1), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_month(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... nw.col("datetime").dt.month().alias("month"), ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_month`: >>> agnostic_dt_month(df_pd) datetime month 0 1978-06-01 6 1 2024-12-13 12 2 2065-01-01 1 >>> agnostic_dt_month(df_pl) shape: (3, 2) ┌─────────────────────┬───────┐ │ datetime ┆ month │ │ --- ┆ --- │ │ datetime[μs] ┆ i8 │ ╞═════════════════════╪═══════╡ │ 1978-06-01 00:00:00 ┆ 6 │ │ 2024-12-13 00:00:00 ┆ 12 │ │ 2065-01-01 00:00:00 ┆ 1 │ └─────────────────────┴───────┘ >>> agnostic_dt_month(df_pa) pyarrow.Table datetime: timestamp[us] month: int64 ---- datetime: [[1978-06-01 00:00:00.000000,2024-12-13 00:00:00.000000,2065-01-01 00:00:00.000000]] month: [[6,12,1]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.month(), self._expr._metadata, ) def day(self: Self) -> ExprT: """Extract day from underlying DateTime representation. Returns the day of month starting from 1. The return value ranges from 1 to 31. (The last day of month differs by months.) Returns: A new expression. Examples: >>> from datetime import datetime >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "datetime": [ ... datetime(1978, 6, 1), ... datetime(2024, 12, 13), ... datetime(2065, 1, 1), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_day(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... nw.col("datetime").dt.day().alias("day"), ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_day`: >>> agnostic_dt_day(df_pd) datetime day 0 1978-06-01 1 1 2024-12-13 13 2 2065-01-01 1 >>> agnostic_dt_day(df_pl) shape: (3, 2) ┌─────────────────────┬─────┐ │ datetime ┆ day │ │ --- ┆ --- │ │ datetime[μs] ┆ i8 │ ╞═════════════════════╪═════╡ │ 1978-06-01 00:00:00 ┆ 1 │ │ 2024-12-13 00:00:00 ┆ 13 │ │ 2065-01-01 00:00:00 ┆ 1 │ └─────────────────────┴─────┘ >>> agnostic_dt_day(df_pa) pyarrow.Table datetime: timestamp[us] day: int64 ---- datetime: [[1978-06-01 00:00:00.000000,2024-12-13 00:00:00.000000,2065-01-01 00:00:00.000000]] day: [[1,13,1]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.day(), self._expr._metadata ) def hour(self: Self) -> ExprT: """Extract hour from underlying DateTime representation. Returns the hour number from 0 to 23. Returns: A new expression. Examples: >>> from datetime import datetime >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "datetime": [ ... datetime(1978, 1, 1, 1), ... datetime(2024, 10, 13, 5), ... datetime(2065, 1, 1, 10), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_hour(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... nw.col("datetime").dt.hour().alias("hour") ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_hour`: >>> agnostic_dt_hour(df_pd) datetime hour 0 1978-01-01 01:00:00 1 1 2024-10-13 05:00:00 5 2 2065-01-01 10:00:00 10 >>> agnostic_dt_hour(df_pl) shape: (3, 2) ┌─────────────────────┬──────┐ │ datetime ┆ hour │ │ --- ┆ --- │ │ datetime[μs] ┆ i8 │ ╞═════════════════════╪══════╡ │ 1978-01-01 01:00:00 ┆ 1 │ │ 2024-10-13 05:00:00 ┆ 5 │ │ 2065-01-01 10:00:00 ┆ 10 │ └─────────────────────┴──────┘ >>> agnostic_dt_hour(df_pa) pyarrow.Table datetime: timestamp[us] hour: int64 ---- datetime: [[1978-01-01 01:00:00.000000,2024-10-13 05:00:00.000000,2065-01-01 10:00:00.000000]] hour: [[1,5,10]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.hour(), self._expr._metadata ) def minute(self: Self) -> ExprT: """Extract minutes from underlying DateTime representation. Returns the minute number from 0 to 59. Returns: A new expression. Examples: >>> from datetime import datetime >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "datetime": [ ... datetime(1978, 1, 1, 1, 1), ... datetime(2024, 10, 13, 5, 30), ... datetime(2065, 1, 1, 10, 20), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_minute(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... nw.col("datetime").dt.minute().alias("minute"), ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_minute`: >>> agnostic_dt_minute(df_pd) datetime minute 0 1978-01-01 01:01:00 1 1 2024-10-13 05:30:00 30 2 2065-01-01 10:20:00 20 >>> agnostic_dt_minute(df_pl) shape: (3, 2) ┌─────────────────────┬────────┐ │ datetime ┆ minute │ │ --- ┆ --- │ │ datetime[μs] ┆ i8 │ ╞═════════════════════╪════════╡ │ 1978-01-01 01:01:00 ┆ 1 │ │ 2024-10-13 05:30:00 ┆ 30 │ │ 2065-01-01 10:20:00 ┆ 20 │ └─────────────────────┴────────┘ >>> agnostic_dt_minute(df_pa) pyarrow.Table datetime: timestamp[us] minute: int64 ---- datetime: [[1978-01-01 01:01:00.000000,2024-10-13 05:30:00.000000,2065-01-01 10:20:00.000000]] minute: [[1,30,20]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.minute(), self._expr._metadata, ) def second(self: Self) -> ExprT: """Extract seconds from underlying DateTime representation. Returns: A new expression. Examples: >>> from datetime import datetime >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "datetime": [ ... datetime(1978, 1, 1, 1, 1, 1), ... datetime(2024, 10, 13, 5, 30, 14), ... datetime(2065, 1, 1, 10, 20, 30), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_second(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... nw.col("datetime").dt.second().alias("second"), ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_second`: >>> agnostic_dt_second(df_pd) datetime second 0 1978-01-01 01:01:01 1 1 2024-10-13 05:30:14 14 2 2065-01-01 10:20:30 30 >>> agnostic_dt_second(df_pl) shape: (3, 2) ┌─────────────────────┬────────┐ │ datetime ┆ second │ │ --- ┆ --- │ │ datetime[μs] ┆ i8 │ ╞═════════════════════╪════════╡ │ 1978-01-01 01:01:01 ┆ 1 │ │ 2024-10-13 05:30:14 ┆ 14 │ │ 2065-01-01 10:20:30 ┆ 30 │ └─────────────────────┴────────┘ >>> agnostic_dt_second(df_pa) pyarrow.Table datetime: timestamp[us] second: int64 ---- datetime: [[1978-01-01 01:01:01.000000,2024-10-13 05:30:14.000000,2065-01-01 10:20:30.000000]] second: [[1,14,30]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.second(), self._expr._metadata, ) def millisecond(self: Self) -> ExprT: """Extract milliseconds from underlying DateTime representation. Returns: A new expression. Examples: >>> from datetime import datetime >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "datetime": [ ... datetime(1978, 1, 1, 1, 1, 1, 0), ... datetime(2024, 10, 13, 5, 30, 14, 505000), ... datetime(2065, 1, 1, 10, 20, 30, 67000), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_millisecond(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... nw.col("datetime").dt.millisecond().alias("millisecond"), ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_millisecond`: >>> agnostic_dt_millisecond(df_pd) datetime millisecond 0 1978-01-01 01:01:01.000 0 1 2024-10-13 05:30:14.505 505 2 2065-01-01 10:20:30.067 67 >>> agnostic_dt_millisecond(df_pl) shape: (3, 2) ┌─────────────────────────┬─────────────┐ │ datetime ┆ millisecond │ │ --- ┆ --- │ │ datetime[μs] ┆ i32 │ ╞═════════════════════════╪═════════════╡ │ 1978-01-01 01:01:01 ┆ 0 │ │ 2024-10-13 05:30:14.505 ┆ 505 │ │ 2065-01-01 10:20:30.067 ┆ 67 │ └─────────────────────────┴─────────────┘ >>> agnostic_dt_millisecond(df_pa) pyarrow.Table datetime: timestamp[us] millisecond: int64 ---- datetime: [[1978-01-01 01:01:01.000000,2024-10-13 05:30:14.505000,2065-01-01 10:20:30.067000]] millisecond: [[0,505,67]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.millisecond(), self._expr._metadata, ) def microsecond(self: Self) -> ExprT: """Extract microseconds from underlying DateTime representation. Returns: A new expression. Examples: >>> from datetime import datetime >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "datetime": [ ... datetime(1978, 1, 1, 1, 1, 1, 0), ... datetime(2024, 10, 13, 5, 30, 14, 505000), ... datetime(2065, 1, 1, 10, 20, 30, 67000), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_microsecond(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... nw.col("datetime").dt.microsecond().alias("microsecond"), ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_microsecond`: >>> agnostic_dt_microsecond(df_pd) datetime microsecond 0 1978-01-01 01:01:01.000 0 1 2024-10-13 05:30:14.505 505000 2 2065-01-01 10:20:30.067 67000 >>> agnostic_dt_microsecond(df_pl) shape: (3, 2) ┌─────────────────────────┬─────────────┐ │ datetime ┆ microsecond │ │ --- ┆ --- │ │ datetime[μs] ┆ i32 │ ╞═════════════════════════╪═════════════╡ │ 1978-01-01 01:01:01 ┆ 0 │ │ 2024-10-13 05:30:14.505 ┆ 505000 │ │ 2065-01-01 10:20:30.067 ┆ 67000 │ └─────────────────────────┴─────────────┘ >>> agnostic_dt_microsecond(df_pa) pyarrow.Table datetime: timestamp[us] microsecond: int64 ---- datetime: [[1978-01-01 01:01:01.000000,2024-10-13 05:30:14.505000,2065-01-01 10:20:30.067000]] microsecond: [[0,505000,67000]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.microsecond(), self._expr._metadata, ) def nanosecond(self: Self) -> ExprT: """Extract Nanoseconds from underlying DateTime representation. Returns: A new expression. Examples: >>> from datetime import datetime >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "datetime": [ ... datetime(1978, 1, 1, 1, 1, 1, 0), ... datetime(2024, 10, 13, 5, 30, 14, 500000), ... datetime(2065, 1, 1, 10, 20, 30, 60000), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_nanosecond(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... nw.col("datetime").dt.nanosecond().alias("nanosecond"), ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_nanosecond`: >>> agnostic_dt_nanosecond(df_pd) datetime nanosecond 0 1978-01-01 01:01:01.000 0 1 2024-10-13 05:30:14.500 500000000 2 2065-01-01 10:20:30.060 60000000 >>> agnostic_dt_nanosecond(df_pl) shape: (3, 2) ┌─────────────────────────┬────────────┐ │ datetime ┆ nanosecond │ │ --- ┆ --- │ │ datetime[μs] ┆ i32 │ ╞═════════════════════════╪════════════╡ │ 1978-01-01 01:01:01 ┆ 0 │ │ 2024-10-13 05:30:14.500 ┆ 500000000 │ │ 2065-01-01 10:20:30.060 ┆ 60000000 │ └─────────────────────────┴────────────┘ >>> agnostic_dt_nanosecond(df_pa) pyarrow.Table datetime: timestamp[us] nanosecond: int64 ---- datetime: [[1978-01-01 01:01:01.000000,2024-10-13 05:30:14.500000,2065-01-01 10:20:30.060000]] nanosecond: [[0,500000000,60000000]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.nanosecond(), self._expr._metadata, ) def ordinal_day(self: Self) -> ExprT: """Get ordinal day. Returns: A new expression. Examples: >>> from datetime import datetime >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = {"a": [datetime(2020, 1, 1), datetime(2020, 8, 3)]} >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_ordinal_day(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... a_ordinal_day=nw.col("a").dt.ordinal_day() ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_ordinal_day`: >>> agnostic_dt_ordinal_day(df_pd) a a_ordinal_day 0 2020-01-01 1 1 2020-08-03 216 >>> agnostic_dt_ordinal_day(df_pl) shape: (2, 2) ┌─────────────────────┬───────────────┐ │ a ┆ a_ordinal_day │ │ --- ┆ --- │ │ datetime[μs] ┆ i16 │ ╞═════════════════════╪═══════════════╡ │ 2020-01-01 00:00:00 ┆ 1 │ │ 2020-08-03 00:00:00 ┆ 216 │ └─────────────────────┴───────────────┘ >>> agnostic_dt_ordinal_day(df_pa) pyarrow.Table a: timestamp[us] a_ordinal_day: int64 ---- a: [[2020-01-01 00:00:00.000000,2020-08-03 00:00:00.000000]] a_ordinal_day: [[1,216]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.ordinal_day(), self._expr._metadata, ) def weekday(self: Self) -> ExprT: """Extract the week day from the underlying Date representation. Returns: Returns the ISO weekday number where monday = 1 and sunday = 7 Examples: >>> from datetime import datetime >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = {"a": [datetime(2020, 1, 1), datetime(2020, 8, 3)]} >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_weekday(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns(a_weekday=nw.col("a").dt.weekday()).to_native() We can then pass either pandas, Polars, PyArrow, and other supported libraries to `agnostic_dt_weekday`: >>> agnostic_dt_weekday(df_pd) a a_weekday 0 2020-01-01 3 1 2020-08-03 1 >>> agnostic_dt_weekday(df_pl) shape: (2, 2) ┌─────────────────────┬───────────┐ │ a ┆ a_weekday │ │ --- ┆ --- │ │ datetime[μs] ┆ i8 │ ╞═════════════════════╪═══════════╡ │ 2020-01-01 00:00:00 ┆ 3 │ │ 2020-08-03 00:00:00 ┆ 1 │ └─────────────────────┴───────────┘ >>> agnostic_dt_weekday(df_pa) pyarrow.Table a: timestamp[us] a_weekday: int64 ---- a: [[2020-01-01 00:00:00.000000,2020-08-03 00:00:00.000000]] a_weekday: [[3,1]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.weekday(), self._expr._metadata, ) def total_minutes(self: Self) -> ExprT: """Get total minutes. Returns: A new expression. Notes: The function outputs the total minutes in the int dtype by default, however, pandas may change the dtype to float when there are missing values, consider using `fill_null()` and `cast` in this case. Examples: >>> from datetime import timedelta >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = {"a": [timedelta(minutes=10), timedelta(minutes=20, seconds=40)]} >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_total_minutes(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... a_total_minutes=nw.col("a").dt.total_minutes() ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_total_minutes`: >>> agnostic_dt_total_minutes(df_pd) a a_total_minutes 0 0 days 00:10:00 10 1 0 days 00:20:40 20 >>> agnostic_dt_total_minutes(df_pl) shape: (2, 2) ┌──────────────┬─────────────────┐ │ a ┆ a_total_minutes │ │ --- ┆ --- │ │ duration[μs] ┆ i64 │ ╞══════════════╪═════════════════╡ │ 10m ┆ 10 │ │ 20m 40s ┆ 20 │ └──────────────┴─────────────────┘ >>> agnostic_dt_total_minutes(df_pa) pyarrow.Table a: duration[us] a_total_minutes: int64 ---- a: [[600000000,1240000000]] a_total_minutes: [[10,20]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.total_minutes(), self._expr._metadata, ) def total_seconds(self: Self) -> ExprT: """Get total seconds. Returns: A new expression. Notes: The function outputs the total seconds in the int dtype by default, however, pandas may change the dtype to float when there are missing values, consider using `fill_null()` and `cast` in this case. Examples: >>> from datetime import timedelta >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "a": [timedelta(seconds=10), timedelta(seconds=20, milliseconds=40)] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_total_seconds(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... a_total_seconds=nw.col("a").dt.total_seconds() ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_total_seconds`: >>> agnostic_dt_total_seconds(df_pd) a a_total_seconds 0 0 days 00:00:10 10 1 0 days 00:00:20.040000 20 >>> agnostic_dt_total_seconds(df_pl) shape: (2, 2) ┌──────────────┬─────────────────┐ │ a ┆ a_total_seconds │ │ --- ┆ --- │ │ duration[μs] ┆ i64 │ ╞══════════════╪═════════════════╡ │ 10s ┆ 10 │ │ 20s 40ms ┆ 20 │ └──────────────┴─────────────────┘ >>> agnostic_dt_total_seconds(df_pa) pyarrow.Table a: duration[us] a_total_seconds: int64 ---- a: [[10000000,20040000]] a_total_seconds: [[10,20]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.total_seconds(), self._expr._metadata, ) def total_milliseconds(self: Self) -> ExprT: """Get total milliseconds. Returns: A new expression. Notes: The function outputs the total milliseconds in the int dtype by default, however, pandas may change the dtype to float when there are missing values, consider using `fill_null()` and `cast` in this case. Examples: >>> from datetime import timedelta >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "a": [ ... timedelta(milliseconds=10), ... timedelta(milliseconds=20, microseconds=40), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_total_milliseconds(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... a_total_milliseconds=nw.col("a").dt.total_milliseconds() ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_total_milliseconds`: >>> agnostic_dt_total_milliseconds(df_pd) a a_total_milliseconds 0 0 days 00:00:00.010000 10 1 0 days 00:00:00.020040 20 >>> agnostic_dt_total_milliseconds(df_pl) shape: (2, 2) ┌──────────────┬──────────────────────┐ │ a ┆ a_total_milliseconds │ │ --- ┆ --- │ │ duration[μs] ┆ i64 │ ╞══════════════╪══════════════════════╡ │ 10ms ┆ 10 │ │ 20040µs ┆ 20 │ └──────────────┴──────────────────────┘ >>> agnostic_dt_total_milliseconds(df_pa) pyarrow.Table a: duration[us] a_total_milliseconds: int64 ---- a: [[10000,20040]] a_total_milliseconds: [[10,20]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.total_milliseconds(), self._expr._metadata, ) def total_microseconds(self: Self) -> ExprT: """Get total microseconds. Returns: A new expression. Notes: The function outputs the total microseconds in the int dtype by default, however, pandas may change the dtype to float when there are missing values, consider using `fill_null()` and `cast` in this case. Examples: >>> from datetime import timedelta >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "a": [ ... timedelta(microseconds=10), ... timedelta(milliseconds=1, microseconds=200), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_total_microseconds(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... a_total_microseconds=nw.col("a").dt.total_microseconds() ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_total_microseconds`: >>> agnostic_dt_total_microseconds(df_pd) a a_total_microseconds 0 0 days 00:00:00.000010 10 1 0 days 00:00:00.001200 1200 >>> agnostic_dt_total_microseconds(df_pl) shape: (2, 2) ┌──────────────┬──────────────────────┐ │ a ┆ a_total_microseconds │ │ --- ┆ --- │ │ duration[μs] ┆ i64 │ ╞══════════════╪══════════════════════╡ │ 10µs ┆ 10 │ │ 1200µs ┆ 1200 │ └──────────────┴──────────────────────┘ >>> agnostic_dt_total_microseconds(df_pa) pyarrow.Table a: duration[us] a_total_microseconds: int64 ---- a: [[10,1200]] a_total_microseconds: [[10,1200]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.total_microseconds(), self._expr._metadata, ) def total_nanoseconds(self: Self) -> ExprT: """Get total nanoseconds. Returns: A new expression. Notes: The function outputs the total nanoseconds in the int dtype by default, however, pandas may change the dtype to float when there are missing values, consider using `fill_null()` and `cast` in this case. Examples: >>> from datetime import timedelta >>> import pandas as pd >>> import polars as pl >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = ["2024-01-01 00:00:00.000000001", "2024-01-01 00:00:00.000000002"] >>> df_pd = pd.DataFrame({"a": pd.to_datetime(data)}) >>> df_pl = pl.DataFrame({"a": data}).with_columns( ... pl.col("a").str.to_datetime(time_unit="ns") ... ) We define a dataframe-agnostic function: >>> def agnostic_dt_total_nanoseconds(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... a_diff_total_nanoseconds=nw.col("a").diff().dt.total_nanoseconds() ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_total_nanoseconds`: >>> agnostic_dt_total_nanoseconds(df_pd) a a_diff_total_nanoseconds 0 2024-01-01 00:00:00.000000001 NaN 1 2024-01-01 00:00:00.000000002 1.0 >>> agnostic_dt_total_nanoseconds(df_pl) shape: (2, 2) ┌───────────────────────────────┬──────────────────────────┐ │ a ┆ a_diff_total_nanoseconds │ │ --- ┆ --- │ │ datetime[ns] ┆ i64 │ ╞═══════════════════════════════╪══════════════════════════╡ │ 2024-01-01 00:00:00.000000001 ┆ null │ │ 2024-01-01 00:00:00.000000002 ┆ 1 │ └───────────────────────────────┴──────────────────────────┘ """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.total_nanoseconds(), self._expr._metadata, ) def to_string(self: Self, format: str) -> ExprT: # noqa: A002 """Convert a Date/Time/Datetime column into a String column with the given format. Arguments: format: Format to format temporal column with. Returns: A new expression. Notes: Unfortunately, different libraries interpret format directives a bit differently. - Chrono, the library used by Polars, uses `"%.f"` for fractional seconds, whereas pandas and Python stdlib use `".%f"`. - PyArrow interprets `"%S"` as "seconds, including fractional seconds" whereas most other tools interpret it as "just seconds, as 2 digits". Therefore, we make the following adjustments: - for pandas-like libraries, we replace `"%S.%f"` with `"%S%.f"`. - for PyArrow, we replace `"%S.%f"` with `"%S"`. Workarounds like these don't make us happy, and we try to avoid them as much as possible, but here we feel like it's the best compromise. If you just want to format a date/datetime Series as a local datetime string, and have it work as consistently as possible across libraries, we suggest using: - `"%Y-%m-%dT%H:%M:%S%.f"` for datetimes - `"%Y-%m-%d"` for dates though note that, even then, different tools may return a different number of trailing zeros. Nonetheless, this is probably consistent enough for most applications. If you have an application where this is not enough, please open an issue and let us know. Examples: >>> from datetime import datetime >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "a": [ ... datetime(2020, 3, 1), ... datetime(2020, 4, 1), ... datetime(2020, 5, 1), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) We define a dataframe-agnostic function: >>> def agnostic_dt_to_string(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.select( ... nw.col("a").dt.to_string("%Y/%m/%d %H:%M:%S") ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_to_string`: >>> agnostic_dt_to_string(df_pd) a 0 2020/03/01 00:00:00 1 2020/04/01 00:00:00 2 2020/05/01 00:00:00 >>> agnostic_dt_to_string(df_pl) shape: (3, 1) ┌─────────────────────┐ │ a │ │ --- │ │ str │ ╞═════════════════════╡ │ 2020/03/01 00:00:00 │ │ 2020/04/01 00:00:00 │ │ 2020/05/01 00:00:00 │ └─────────────────────┘ >>> agnostic_dt_to_string(df_pa) pyarrow.Table a: string ---- a: [["2020/03/01 00:00:00.000000","2020/04/01 00:00:00.000000","2020/05/01 00:00:00.000000"]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.to_string(format), self._expr._metadata, ) def replace_time_zone(self: Self, time_zone: str | None) -> ExprT: """Replace time zone. Arguments: time_zone: Target time zone. Returns: A new expression. Examples: >>> from datetime import datetime, timezone >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "a": [ ... datetime(2024, 1, 1, tzinfo=timezone.utc), ... datetime(2024, 1, 2, tzinfo=timezone.utc), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) Let's define a dataframe-agnostic function: >>> def agnostic_dt_replace_time_zone(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.select( ... nw.col("a").dt.replace_time_zone("Asia/Kathmandu") ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_replace_time_zone`: >>> agnostic_dt_replace_time_zone(df_pd) a 0 2024-01-01 00:00:00+05:45 1 2024-01-02 00:00:00+05:45 >>> agnostic_dt_replace_time_zone(df_pl) shape: (2, 1) ┌──────────────────────────────┐ │ a │ │ --- │ │ datetime[μs, Asia/Kathmandu] │ ╞══════════════════════════════╡ │ 2024-01-01 00:00:00 +0545 │ │ 2024-01-02 00:00:00 +0545 │ └──────────────────────────────┘ >>> agnostic_dt_replace_time_zone(df_pa) pyarrow.Table a: timestamp[us, tz=Asia/Kathmandu] ---- a: [[2023-12-31 18:15:00.000000Z,2024-01-01 18:15:00.000000Z]] """ return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.replace_time_zone( time_zone ), self._expr._metadata, ) def convert_time_zone(self: Self, time_zone: str) -> ExprT: """Convert to a new time zone. If converting from a time-zone-naive column, then conversion happens as if converting from UTC. Arguments: time_zone: Target time zone. Returns: A new expression. Examples: >>> from datetime import datetime, timezone >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = { ... "a": [ ... datetime(2024, 1, 1, tzinfo=timezone.utc), ... datetime(2024, 1, 2, tzinfo=timezone.utc), ... ] ... } >>> df_pd = pd.DataFrame(data) >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) Let's define a dataframe-agnostic function: >>> def agnostic_dt_convert_time_zone(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.select( ... nw.col("a").dt.convert_time_zone("Asia/Kathmandu") ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_convert_time_zone`: >>> agnostic_dt_convert_time_zone(df_pd) a 0 2024-01-01 05:45:00+05:45 1 2024-01-02 05:45:00+05:45 >>> agnostic_dt_convert_time_zone(df_pl) shape: (2, 1) ┌──────────────────────────────┐ │ a │ │ --- │ │ datetime[μs, Asia/Kathmandu] │ ╞══════════════════════════════╡ │ 2024-01-01 05:45:00 +0545 │ │ 2024-01-02 05:45:00 +0545 │ └──────────────────────────────┘ >>> agnostic_dt_convert_time_zone(df_pa) pyarrow.Table a: timestamp[us, tz=Asia/Kathmandu] ---- a: [[2024-01-01 00:00:00.000000Z,2024-01-02 00:00:00.000000Z]] """ if time_zone is None: msg = "Target `time_zone` cannot be `None` in `convert_time_zone`. Please use `replace_time_zone(None)` if you want to remove the time zone." raise TypeError(msg) return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.convert_time_zone( time_zone ), self._expr._metadata, ) def timestamp(self: Self, time_unit: TimeUnit = "us") -> ExprT: """Return a timestamp in the given time unit. Arguments: time_unit: {'ns', 'us', 'ms'} Time unit. Returns: A new expression. Examples: >>> from datetime import date >>> import pandas as pd >>> import polars as pl >>> import pyarrow as pa >>> import narwhals as nw >>> from narwhals.typing import IntoFrameT >>> >>> data = {"date": [date(2001, 1, 1), None, date(2001, 1, 3)]} >>> df_pd = pd.DataFrame(data, dtype="datetime64[ns]") >>> df_pl = pl.DataFrame(data) >>> df_pa = pa.table(data) Let's define a dataframe-agnostic function: >>> def agnostic_dt_timestamp(df_native: IntoFrameT) -> IntoFrameT: ... df = nw.from_native(df_native) ... return df.with_columns( ... nw.col("date").dt.timestamp().alias("timestamp_us"), ... nw.col("date").dt.timestamp("ms").alias("timestamp_ms"), ... ).to_native() We can then pass any supported library such as pandas, Polars, or PyArrow to `agnostic_dt_timestamp`: >>> agnostic_dt_timestamp(df_pd) date timestamp_us timestamp_ms 0 2001-01-01 9.783072e+14 9.783072e+11 1 NaT NaN NaN 2 2001-01-03 9.784800e+14 9.784800e+11 >>> agnostic_dt_timestamp(df_pl) shape: (3, 3) ┌────────────┬─────────────────┬──────────────┐ │ date ┆ timestamp_us ┆ timestamp_ms │ │ --- ┆ --- ┆ --- │ │ date ┆ i64 ┆ i64 │ ╞════════════╪═════════════════╪══════════════╡ │ 2001-01-01 ┆ 978307200000000 ┆ 978307200000 │ │ null ┆ null ┆ null │ │ 2001-01-03 ┆ 978480000000000 ┆ 978480000000 │ └────────────┴─────────────────┴──────────────┘ >>> agnostic_dt_timestamp(df_pa) pyarrow.Table date: date32[day] timestamp_us: int64 timestamp_ms: int64 ---- date: [[2001-01-01,null,2001-01-03]] timestamp_us: [[978307200000000,null,978480000000000]] timestamp_ms: [[978307200000,null,978480000000]] """ if time_unit not in {"ns", "us", "ms"}: msg = ( "invalid `time_unit`" f"\n\nExpected one of {{'ns', 'us', 'ms'}}, got {time_unit!r}." ) raise ValueError(msg) return self._expr.__class__( lambda plx: self._expr._to_compliant_expr(plx).dt.timestamp(time_unit), self._expr._metadata, )