Add first and last method to IndexedFrame
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
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@@ -3,9 +3,10 @@ | |
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| from __future__ import annotations | ||
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| import operator | ||
| import warnings | ||
| from collections import abc | ||
| from typing import Callable, Type, TypeVar | ||
| from uuid import uuid4 | ||
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| import cupy as cp | ||
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@@ -109,6 +110,7 @@ class IndexedFrame(Frame): | |
| # mypy can't handle bound type variables as class members | ||
| _loc_indexer_type: Type[_LocIndexerClass] # type: ignore | ||
| _iloc_indexer_type: Type[_IlocIndexerClass] # type: ignore | ||
| _index: cudf.core.index.BaseIndex | ||
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| def __init__(self, data=None, index=None): | ||
| super().__init__(data=data, index=index) | ||
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@@ -1104,3 +1106,125 @@ def resample( | |
| if isinstance(self, cudf.Series) | ||
| else cudf.core.resample.DataFrameResampler(self, by=by) | ||
| ) | ||
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| def _first_or_last( | ||
| self, offset, idx: int, op: Callable, side: str, slice_func: Callable | ||
| ) -> "IndexedFrame": | ||
| """Shared code path for ``first`` and ``last``.""" | ||
| if not isinstance(self._index, cudf.core.index.DatetimeIndex): | ||
| raise TypeError("'first' only supports a DatetimeIndex index.") | ||
| if not isinstance(offset, str): | ||
| raise NotImplementedError( | ||
| f"Unsupported offset type {type(offset)}." | ||
| ) | ||
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| if len(self) == 0: | ||
| return self.copy() | ||
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| pd_offset = pd.tseries.frequencies.to_offset(offset) | ||
| to_search = op(pd.Timestamp(self._index._column[idx]), pd_offset) | ||
| if ( | ||
| idx == 0 | ||
| and not isinstance(pd_offset, pd.tseries.offsets.Tick) | ||
| and pd_offset.is_on_offset(pd.Timestamp(self._index[0])) | ||
|
There was a problem hiding this comment. does There was a problem hiding this comment. I think pandas In [3]: pd.tseries.frequencies.to_offset('M')
Out[3]: <MonthEnd>
In [4]: pd.tseries.frequencies.to_offset('MS')
Out[4]: <MonthBegin>I believe Like and and for |
||
| ): | ||
| # Special handle is required when the start time of the index | ||
| # is on the end of the offset. See pandas gh29623 for detail. | ||
| to_search = to_search - pd_offset.base | ||
| return self.loc[:to_search] | ||
| end_point = int( | ||
| self._index._column.searchsorted(to_search, side=side)[0] | ||
| ) | ||
| return slice_func(end_point) | ||
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| def first(self, offset): | ||
| """Select initial periods of time series data based on a date offset. | ||
| When having a DataFrame with **sorted** dates as index, this function | ||
| can select the first few rows based on a date offset. | ||
| Parameters | ||
| ---------- | ||
| offset: str | ||
| The offset length of the data that will be selected. For intance, | ||
| '1M' will display all rows having their index within the first | ||
| month. | ||
| Returns | ||
| ------- | ||
| Series or DataFrame | ||
| A subset of the caller. | ||
| Raises | ||
| ------ | ||
| TypeError | ||
| If the index is not a ``DatetimeIndex`` | ||
| Examples | ||
| -------- | ||
| >>> i = cudf.date_range('2018-04-09', periods=4, freq='2D') | ||
| >>> ts = cudf.DataFrame({'A': [1, 2, 3, 4]}, index=i) | ||
| >>> ts | ||
| A | ||
| 2018-04-09 1 | ||
| 2018-04-11 2 | ||
| 2018-04-13 3 | ||
| 2018-04-15 4 | ||
| >>> ts.first('3D') | ||
| A | ||
| 2018-04-09 1 | ||
| 2018-04-11 2 | ||
| """ | ||
| return self._first_or_last( | ||
| offset, | ||
| idx=0, | ||
| op=operator.__add__, | ||
| side="left", | ||
| slice_func=lambda i: self.iloc[:i], | ||
| ) | ||
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| def last(self, offset): | ||
| """Select final periods of time series data based on a date offset. | ||
| When having a DataFrame with **sorted** dates as index, this function | ||
| can select the last few rows based on a date offset. | ||
| Parameters | ||
| ---------- | ||
| offset: str | ||
| The offset length of the data that will be selected. For instance, | ||
| '3D' will display all rows having their index within the last 3 | ||
| days. | ||
| Returns | ||
| ------- | ||
| Series or DataFrame | ||
| A subset of the caller. | ||
| Raises | ||
| ------ | ||
| TypeError | ||
| If the index is not a ``DatetimeIndex`` | ||
| Examples | ||
| -------- | ||
| >>> i = cudf.date_range('2018-04-09', periods=4, freq='2D') | ||
| >>> ts = cudf.DataFrame({'A': [1, 2, 3, 4]}, index=i) | ||
| >>> ts | ||
| A | ||
| 2018-04-09 1 | ||
| 2018-04-11 2 | ||
| 2018-04-13 3 | ||
| 2018-04-15 4 | ||
| >>> ts.last('3D') | ||
| A | ||
| 2018-04-13 3 | ||
| 2018-04-15 4 | ||
| """ | ||
| return self._first_or_last( | ||
| offset, | ||
| idx=-1, | ||
| op=operator.__sub__, | ||
| side="right", | ||
| slice_func=lambda i: self.iloc[i:], | ||
| ) | ||
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What does the
opcallable do? and what is the operation being done in this line // what doesto_searchrepr? jwThere was a problem hiding this comment.
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If
firstis called, thenopisaddto compute the cut-off date counting from the first date in the column; iflast,opissubto compute the that from the last date.to_searchis the cut-off date. Feel free to request changes if the naming/logic isn't very readable to your taste.