Pandas Tips

pandas_cookbook.py

import pandas as pd

def filter_columns_by_keyword(df: pd.DataFrame, keyword: str)-> pd.DataFrame:
    """Filters pandas columns by a keyword by searching the column index for a matching substring"""
    return df.loc[:, lambda d: d.columns.str.contains(keyword)]

def convert_monthly_ts(df):
    return df.reset_index().assign(ds_month = lambda x: x.ds + pd.offsets.MonthBegin()).groupby(["job_area", "ds_month"], as_index=False).y.mean()


source = pd.merge(
    df_forecast.pipe(convert_monthly_ts),
    df_es.pipe(convert_monthly_ts),
    on=["job_area", "ds_month"],
    suffixes=("_rolling", "_expanding"),
)

# convert two number columns to a single column with an identifier column for visualization
source = source.melt(id_vars=["job_area", "ds_month"], value_vars=["y_rolling", "y_expanding"], var_name="statistic", value_name="y")