Wednesday, 1 December 2021

Apply rolling as part of a column calcuation?

I'm looking to create a new column that finds the minimum offset value (i.e. number of rows back) of the minimum value in a specific window, only problem is the window size changes from row to row.

A way to find the minimum offset value from the current row using a static number, is to reverse the order of the column, and then apply the argmin function with a shift, like so:

df['initx1'] = df['Close'][::-1].rolling(20).apply(np.argmin, raw=True).shift(-(20 + 1))

...however, what I'd like to do is use a dynamic rolling number without having to resort to using a for loop, I want this done as a column calculation like the above. The psuedo-code of what I'm attempting looks like this:

df['initx1'] = df['Close'][::-1].rolling(df['dynamicWindowSize']).apply(np.argmin, raw=True).shift(-(df['dynamicWindowSize'] + 1))

...but of course it throws an error saying rolling should be an integer, even though the series in df['dynamicWindowSize'] ARE all integers, but I know it's because I'm passing in a series. Any ideas?

A reproducible dataset is provided below to work with:

import numpy as np
import pandas as pd
from datetime import datetime

# Create a reproducible, static dataframe.
# 1 minute SPY data. Skip to the bottom...
df = pd.DataFrame([
    {
        "time": "2021-10-26 9:30",
        "open": "457.2",
        "high": "457.29",
        "low": "456.78",
        "close": "456.9383",
        "volume": "594142"
    },
    {
        "time": "2021-10-26 9:31",
        "open": "456.94",
        "high": "457.07",
        "low": "456.8",
        "close": "456.995",
        "volume": "194061"
    },
    {
        "time": "2021-10-26 9:32",
        "open": "456.99",
        "high": "457.22",
        "low": "456.84",
        "close": "457.21",
        "volume": "186114"
    },
    {
        "time": "2021-10-26 9:33",
        "open": "457.22",
        "high": "457.45",
        "low": "457.2011",
        "close": "457.308",
        "volume": "294158"
    },
    {
        "time": "2021-10-26 9:34",
        "open": "457.31",
        "high": "457.4",
        "low": "457.25",
        "close": "457.32",
        "volume": "172574"
    },
    {
        "time": "2021-10-26 9:35",
        "open": "457.31",
        "high": "457.48",
        "low": "457.18",
        "close": "457.44",
        "volume": "396668"
    },
    {
        "time": "2021-10-26 9:36",
        "open": "457.48",
        "high": "457.6511",
        "low": "457.44",
        "close": "457.57",
        "volume": "186777"
    },
    {
        "time": "2021-10-26 9:37",
        "open": "457.5699",
        "high": "457.73",
        "low": "457.5699",
        "close": "457.69",
        "volume": "187596"
    },
    {
        "time": "2021-10-26 9:38",
        "open": "457.7",
        "high": "457.73",
        "low": "457.54",
        "close": "457.63",
        "volume": "185570"
    },
    {
        "time": "2021-10-26 9:39",
        "open": "457.63",
        "high": "457.64",
        "low": "457.31",
        "close": "457.59",
        "volume": "164707"
    },
    {
        "time": "2021-10-26 9:40",
        "open": "457.59",
        "high": "457.72",
        "low": "457.46",
        "close": "457.7199",
        "volume": "167438"
    },
    {
        "time": "2021-10-26 9:41",
        "open": "457.72",
        "high": "457.8",
        "low": "457.68",
        "close": "457.72",
        "volume": "199951"
    },
    {
        "time": "2021-10-26 9:42",
        "open": "457.73",
        "high": "457.74",
        "low": "457.6",
        "close": "457.62",
        "volume": "152134"
    },
    {
        "time": "2021-10-26 9:43",
        "open": "457.6",
        "high": "457.65",
        "low": "457.45",
        "close": "457.5077",
        "volume": "142530"
    },
    {
        "time": "2021-10-26 9:44",
        "open": "457.51",
        "high": "457.64",
        "low": "457.4001",
        "close": "457.61",
        "volume": "122575"
    },
    {
        "time": "2021-10-26 9:45",
        "open": "457.61",
        "high": "457.76",
        "low": "457.58",
        "close": "457.75",
        "volume": "119886"
    },
    {
        "time": "2021-10-26 9:46",
        "open": "457.74",
        "high": "457.75",
        "low": "457.37",
        "close": "457.38",
        "volume": "183157"
    },
    {
        "time": "2021-10-26 9:47",
        "open": "457.42",
        "high": "457.49",
        "low": "457.37",
        "close": "457.44",
        "volume": "128542"
    },
    {
        "time": "2021-10-26 9:48",
        "open": "457.43",
        "high": "457.49",
        "low": "457.33",
        "close": "457.44",
        "volume": "154181"
    },
    {
        "time": "2021-10-26 9:49",
        "open": "457.43",
        "high": "457.5898",
        "low": "457.42",
        "close": "457.47",
        "volume": "163063"
    },
    {
        "time": "2021-10-26 9:50",
        "open": "457.45",
        "high": "457.59",
        "low": "457.44",
        "close": "457.555",
        "volume": "96229"
    },
    {
        "time": "2021-10-26 9:51",
        "open": "457.56",
        "high": "457.61",
        "low": "457.31",
        "close": "457.4217",
        "volume": "110380"
    },
    {
        "time": "2021-10-26 9:52",
        "open": "457.42",
        "high": "457.56",
        "low": "457.42",
        "close": "457.47",
        "volume": "107518"
    },
    {
        "time": "2021-10-26 9:53",
        "open": "457.475",
        "high": "457.51",
        "low": "457.4",
        "close": "457.48",
        "volume": "78062"
    },
    {
        "time": "2021-10-26 9:54",
        "open": "457.49",
        "high": "457.57",
        "low": "457.42",
        "close": "457.46",
        "volume": "133883"
    },
    {
        "time": "2021-10-26 9:55",
        "open": "457.47",
        "high": "457.56",
        "low": "457.45",
        "close": "457.51",
        "volume": "98998"
    },
    {
        "time": "2021-10-26 9:56",
        "open": "457.51",
        "high": "457.54",
        "low": "457.43",
        "close": "457.43",
        "volume": "110237"
    },
    {
        "time": "2021-10-26 9:57",
        "open": "457.43",
        "high": "457.65",
        "low": "457.375",
        "close": "457.65",
        "volume": "98794"
    },
    {
        "time": "2021-10-26 9:58",
        "open": "457.66",
        "high": "457.69",
        "low": "457.35",
        "close": "457.45",
        "volume": "262154"
    },
    {
        "time": "2021-10-26 9:59",
        "open": "457.45",
        "high": "457.47",
        "low": "457.33",
        "close": "457.4",
        "volume": "74685"
    },
    {
        "time": "2021-10-26 10:00",
        "open": "457.41",
        "high": "457.48",
        "low": "457.18",
        "close": "457.38",
        "volume": "166617"
    },
    {
        "time": "2021-10-26 10:01",
        "open": "457.39",
        "high": "457.7",
        "low": "457.39",
        "close": "457.5",
        "volume": "265649"
    },
    {
        "time": "2021-10-26 10:02",
        "open": "457.51",
        "high": "457.57",
        "low": "457.39",
        "close": "457.53",
        "volume": "131947"
    },
    {
        "time": "2021-10-26 10:03",
        "open": "457.53",
        "high": "457.54",
        "low": "457.4",
        "close": "457.51",
        "volume": "80111"
    },
    {
        "time": "2021-10-26 10:04",
        "open": "457.51",
        "high": "457.62",
        "low": "457.5",
        "close": "457.6101",
        "volume": "117174"
    },
    {
        "time": "2021-10-26 10:05",
        "open": "457.621",
        "high": "457.64",
        "low": "457.51",
        "close": "457.58",
        "volume": "168758"
    },
    {
        "time": "2021-10-26 10:06",
        "open": "457.58",
        "high": "457.64",
        "low": "457.46",
        "close": "457.61",
        "volume": "84076"
    },
    {
        "time": "2021-10-26 10:07",
        "open": "457.62",
        "high": "457.7401",
        "low": "457.62",
        "close": "457.66",
        "volume": "125156"
    },
    {
        "time": "2021-10-26 10:08",
        "open": "457.665",
        "high": "457.69",
        "low": "457.5",
        "close": "457.67",
        "volume": "116919"
    },
    {
        "time": "2021-10-26 10:09",
        "open": "457.69",
        "high": "457.72",
        "low": "457.5",
        "close": "457.57",
        "volume": "102551"
    },
    {
        "time": "2021-10-26 10:10",
        "open": "457.56",
        "high": "457.75",
        "low": "457.56",
        "close": "457.7",
        "volume": "109165"
    },
    {
        "time": "2021-10-26 10:11",
        "open": "457.7",
        "high": "457.725",
        "low": "457.63",
        "close": "457.66",
        "volume": "146209"
    },
    {
        "time": "2021-10-26 10:12",
        "open": "457.665",
        "high": "457.88",
        "low": "457.64",
        "close": "457.86",
        "volume": "210620"
    },
    {
        "time": "2021-10-26 10:13",
        "open": "457.855",
        "high": "457.96",
        "low": "457.83",
        "close": "457.95",
        "volume": "159975"
    },
    {
        "time": "2021-10-26 10:14",
        "open": "457.95",
        "high": "458.02",
        "low": "457.93",
        "close": "457.95",
        "volume": "152042"
    },
    {
        "time": "2021-10-26 10:15",
        "open": "457.96",
        "high": "458.15",
        "low": "457.96",
        "close": "458.08",
        "volume": "146047"
    },
    {
        "time": "2021-10-26 10:16",
        "open": "458.085",
        "high": "458.17",
        "low": "457.99",
        "close": "458.15",
        "volume": "100732"
    },
    {
        "time": "2021-10-26 10:17",
        "open": "458.17",
        "high": "458.33",
        "low": "458.155",
        "close": "458.245",
        "volume": "235072"
    },
    {
        "time": "2021-10-26 10:18",
        "open": "458.25",
        "high": "458.29",
        "low": "458.14",
        "close": "458.16",
        "volume": "422002"
    },
    {
        "time": "2021-10-26 10:19",
        "open": "458.17",
        "high": "458.2801",
        "low": "458.1699",
        "close": "458.28",
        "volume": "114611"
    },
    {
        "time": "2021-10-26 10:20",
        "open": "458.29",
        "high": "458.39",
        "low": "458.24",
        "close": "458.37",
        "volume": "241797"
    },
    {
        "time": "2021-10-26 10:21",
        "open": "458.37",
        "high": "458.42",
        "low": "458.31",
        "close": "458.345",
        "volume": "124824"
    },
    {
        "time": "2021-10-26 10:22",
        "open": "458.33",
        "high": "458.49",
        "low": "458.33",
        "close": "458.47",
        "volume": "132125"
    }
])

# Convert df to numeric and time to datetime re: the .csv to .json
# converter tool I used online...
df[['open','high','low','close','volume']] = df[['open','high','low','close','volume']].apply(pd.to_numeric)
df['time'] = pd.to_datetime(df['time'])


from Apply rolling as part of a column calcuation?

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