Source code for featuretools.primitives.standard.transform.time_series.rolling_max

import pandas as pd
from woodwork.column_schema import ColumnSchema
from woodwork.logical_types import Datetime, Double

from featuretools.primitives.base.transform_primitive_base import TransformPrimitive
from featuretools.primitives.standard.transform.time_series.utils import (
    apply_rolling_agg_to_series,
)


[docs]class RollingMax(TransformPrimitive): """Determines the maximum of entries over a given window. Description: Given a list of numbers and a corresponding list of datetimes, return a rolling maximum of the numeric values, starting at the row `gap` rows away from the current row and looking backward over the specified window (by `window_length` and `gap`). Input datetimes should be monotonic. Args: window_length (int, string, optional): Specifies the amount of data included in each window. If an integer is provided, it will correspond to a number of rows. For data with a uniform sampling frequency, for example of one day, the window_length will correspond to a period of time, in this case, 7 days for a window_length of 7. If a string is provided, it must be one of pandas' offset alias strings ('1D', '1H', etc), and it will indicate a length of time that each window should span. The list of available offset aliases can be found at https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases. Defaults to 3. gap (int, string, optional): Specifies a gap backwards from each instance before the window of usable data begins. If an integer is provided, it will correspond to a number of rows. If a string is provided, it must be one of pandas' offset alias strings ('1D', '1H', etc), and it will indicate a length of time between a target instance and the beginning of its window. Defaults to 1. min_periods (int, optional): Minimum number of observations required for performing calculations over the window. Can only be as large as window_length when window_length is an integer. When window_length is an offset alias string, this limitation does not exist, but care should be taken to not choose a min_periods that will always be larger than the number of observations in a window. Defaults to 1. Note: Only offset aliases with fixed frequencies can be used when defining gap and window_length. This means that aliases such as `M` or `W` cannot be used, as they can indicate different numbers of days. ('M', because different months have different numbers of days; 'W' because week will indicate a certain day of the week, like W-Wed, so that will indicate a different number of days depending on the anchoring date.) Note: When using an offset alias to define `gap`, an offset alias must also be used to define `window_length`. This limitation does not exist when using an offset alias to define `window_length`. In fact, if the data has a uniform sampling frequency, it is preferable to use a numeric `gap` as it is more efficient. Examples: >>> import pandas as pd >>> rolling_max = RollingMax(window_length=3) >>> times = pd.date_range(start='2019-01-01', freq='1min', periods=5) >>> rolling_max(times, [4, 3, 2, 1, 0]).tolist() [nan, 4.0, 4.0, 4.0, 3.0] We can also control the gap before the rolling calculation. >>> import pandas as pd >>> rolling_max = RollingMax(window_length=3, gap=0) >>> times = pd.date_range(start='2019-01-01', freq='1min', periods=5) >>> rolling_max(times, [4, 3, 2, 1, 0]).tolist() [4.0, 4.0, 4.0, 3.0, 2.0] We can also control the minimum number of periods required for the rolling calculation. >>> import pandas as pd >>> rolling_max = RollingMax(window_length=3, min_periods=3, gap=0) >>> times = pd.date_range(start='2019-01-01', freq='1min', periods=5) >>> rolling_max(times, [4, 3, 2, 1, 0]).tolist() [nan, nan, 4.0, 3.0, 2.0] We can also set the window_length and gap using offset alias strings. >>> import pandas as pd >>> rolling_max = RollingMax(window_length='3min', gap='1min') >>> times = pd.date_range(start='2019-01-01', freq='1min', periods=5) >>> rolling_max(times, [4, 3, 2, 1, 0]).tolist() [nan, 4.0, 4.0, 4.0, 3.0] """ name = "rolling_max" input_types = [ ColumnSchema(logical_type=Datetime, semantic_tags={"time_index"}), ColumnSchema(semantic_tags={"numeric"}), ] return_type = ColumnSchema(logical_type=Double, semantic_tags={"numeric"}) uses_full_dataframe = True
[docs] def __init__(self, window_length=3, gap=1, min_periods=1): self.window_length = window_length self.gap = gap self.min_periods = min_periods
def get_function(self): def rolling_max(datetime, numeric): x = pd.Series(numeric.values, index=datetime.values) return apply_rolling_agg_to_series( x, lambda series: series.max(), self.window_length, self.gap, self.min_periods, ) return rolling_max