Source code for mars.dataframe.tseries.to_datetime

# Copyright 1999-2021 Alibaba Group Holding Ltd.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# See the License for the specific language governing permissions and
# limitations under the License.

from functools import partial
from typing import Any

import numpy as np
import pandas as pd
from pandas.api.types import is_scalar, is_dict_like

from ... import opcodes
from ...core import recursive_tile
from ...serialization.serializables import KeyField, StringField, BoolField, AnyField
from ...tensor import tensor as astensor
from ...tensor.core import TENSOR_CHUNK_TYPE
from ..initializer import DataFrame as asdataframe, Series as asseries, Index as asindex
from ..operands import DataFrameOperand, DataFrameOperandMixin
from ..utils import parse_index, lazy_import

cudf = lazy_import("cudf")

class DataFrameToDatetime(DataFrameOperand, DataFrameOperandMixin):
    _op_type_ = opcodes.TO_DATETIME

    arg = KeyField("arg")
    errors = StringField("errors", default=None)
    dayfirst = BoolField("dayfirst", default=None)
    yearfirst = BoolField("yearfirst", default=None)
    utc = BoolField("utc", default=None)
    format = StringField("format", default=None)
    exact = BoolField("exact", default=None)
    unit = StringField("unit", default=None)
    infer_datetime_format = BoolField("infer_datetime_format", default=None)
    origin = AnyField("origin", default=None)
    cache = BoolField("cache", default=None)

    def _params(self):
        return tuple(
            getattr(self, k)
            for k in self._keys_
            if k not in self._no_copy_attrs_ and k != "arg" and hasattr(self, k)

    def _set_inputs(self, inputs):
        self.arg = self._inputs[0]

    def __call__(self, arg):
        if is_scalar(arg):
            ret = pd.to_datetime(
            return astensor(ret)

        dtype = np.datetime64(1, "ns").dtype
        if isinstance(arg, (pd.Series, SERIES_TYPE)):
            arg = asseries(arg)
            return self.new_series(
        if is_dict_like(arg) or isinstance(arg, DATAFRAME_TYPE):
            arg = asdataframe(arg)
            columns = arg.columns_value.to_pandas().tolist()
            if sorted(columns) != sorted(["year", "month", "day"]):
                missing = ",".join(
                    c for c in ["day", "month", "year"] if c not in columns
                raise ValueError(
                    "to assemble mappings requires at least "
                    f"that [year, month, day] be specified: [{missing}] is missing"
            return self.new_series(
                [arg], shape=(arg.shape[0],), dtype=dtype, index_value=arg.index_value
        elif isinstance(arg, (pd.Index, INDEX_TYPE)):
            arg = asindex(arg)
            return self.new_index(
                index_value=parse_index(pd.Index([], dtype=dtype), self._params, arg),
            arg = astensor(arg)
            if arg.ndim != 1:
                raise TypeError(
                    "arg must be a string, datetime, "
                    "list, tuple, 1-d tensor, or Series"
            return self.new_index(
                index_value=parse_index(pd.Index([], dtype=dtype), self._params, arg),

    def tile(cls, op: "DataFrameToDatetime"):
        out = op.outputs[0]
        arg = op.arg

        if isinstance(arg, DATAFRAME_TYPE):
            if np.isnan(arg.shape[0]) or any(
                np.isnan(s) for s in arg.nsplits[1]
            ):  # pragma: no cover

            arg = yield from recursive_tile(arg.rechunk({1: arg.shape[1]}))

        out_chunks = []
        for chunk in arg.chunks:
            chunk_op = op.copy().reset_key()
            if isinstance(chunk, (TENSOR_CHUNK_TYPE, INDEX_CHUNK_TYPE)):
                chunk_index_value = parse_index(
                    pd.Index([], dtype=out.dtype), op._params, chunk
                chunk_index_value = chunk.index_value

            out_chunk = chunk_op.new_chunk(

        params = out.params
        params["nsplits"] = (arg.nsplits[0],)
        params["chunks"] = out_chunks
        new_op = op.copy()
        return new_op.new_tileables(op.inputs, kws=[params])

    def execute(cls, ctx, op: "DataFrameToDatetime"):
        arg = ctx[op.arg.key]

        unit = op.unit
        if cudf and op.gpu:
            func = cudf.to_datetime
            if unit is None:
                unit = "ns"
            func = pd.to_datetime

        call = partial(

            ctx[op.outputs[0].key] = call(arg)
        except ValueError:  # pragma: no cover
            ctx[op.outputs[0].key] = call(arg.copy())

[docs]def to_datetime( arg, errors: str = "raise", dayfirst: bool = False, yearfirst: bool = False, utc: bool = None, format: str = None, exact: bool = True, unit: str = None, infer_datetime_format: bool = False, origin: Any = "unix", cache: bool = True, ): """ Convert argument to datetime. Parameters ---------- arg : int, float, str, datetime, list, tuple, 1-d array, Series DataFrame/dict-like The object to convert to a datetime. errors : {'ignore', 'raise', 'coerce'}, default 'raise' - If 'raise', then invalid parsing will raise an exception. - If 'coerce', then invalid parsing will be set as NaT. - If 'ignore', then invalid parsing will return the input. dayfirst : bool, default False Specify a date parse order if `arg` is str or its list-likes. If True, parses dates with the day first, eg 10/11/12 is parsed as 2012-11-10. Warning: dayfirst=True is not strict, but will prefer to parse with day first (this is a known bug, based on dateutil behavior). yearfirst : bool, default False Specify a date parse order if `arg` is str or its list-likes. - If True parses dates with the year first, eg 10/11/12 is parsed as 2010-11-12. - If both dayfirst and yearfirst are True, yearfirst is preceded (same as dateutil). Warning: yearfirst=True is not strict, but will prefer to parse with year first (this is a known bug, based on dateutil behavior). utc : bool, default None Return UTC DatetimeIndex if True (converting any tz-aware datetime.datetime objects as well). format : str, default None The strftime to parse time, eg "%d/%m/%Y", note that "%f" will parse all the way up to nanoseconds. See strftime documentation for more information on choices: exact : bool, True by default Behaves as: - If True, require an exact format match. - If False, allow the format to match anywhere in the target string. unit : str, default 'ns' The unit of the arg (D,s,ms,us,ns) denote the unit, which is an integer or float number. This will be based off the origin. Example, with unit='ms' and origin='unix' (the default), this would calculate the number of milliseconds to the unix epoch start. infer_datetime_format : bool, default False If True and no `format` is given, attempt to infer the format of the datetime strings, and if it can be inferred, switch to a faster method of parsing them. In some cases this can increase the parsing speed by ~5-10x. origin : scalar, default 'unix' Define the reference date. The numeric values would be parsed as number of units (defined by `unit`) since this reference date. - If 'unix' (or POSIX) time; origin is set to 1970-01-01. - If 'julian', unit must be 'D', and origin is set to beginning of Julian Calendar. Julian day number 0 is assigned to the day starting at noon on January 1, 4713 BC. - If Timestamp convertible, origin is set to Timestamp identified by origin. cache : bool, default True If True, use a cache of unique, converted dates to apply the datetime conversion. May produce significant speed-up when parsing duplicate date strings, especially ones with timezone offsets. The cache is only used when there are at least 50 values. The presence of out-of-bounds values will render the cache unusable and may slow down parsing. Returns ------- datetime If parsing succeeded. Return type depends on input: - list-like: DatetimeIndex - Series: Series of datetime64 dtype - scalar: Timestamp In case when it is not possible to return designated types (e.g. when any element of input is before Timestamp.min or after Timestamp.max) return will have datetime.datetime type (or corresponding array/Series). See Also -------- DataFrame.astype : Cast argument to a specified dtype. to_timedelta : Convert argument to timedelta. convert_dtypes : Convert dtypes. Examples -------- Assembling a datetime from multiple columns of a DataFrame. The keys can be common abbreviations like ['year', 'month', 'day', 'minute', 'second', 'ms', 'us', 'ns']) or plurals of the same >>> import mars.dataframe as md >>> df = md.DataFrame({'year': [2015, 2016], ... 'month': [2, 3], ... 'day': [4, 5]}) >>> md.to_datetime(df).execute() 0 2015-02-04 1 2016-03-05 dtype: datetime64[ns] If a date does not meet the `timestamp limitations < #timeseries-timestamp-limits>`_, passing errors='ignore' will return the original input instead of raising any exception. Passing errors='coerce' will force an out-of-bounds date to NaT, in addition to forcing non-dates (or non-parseable dates) to NaT. >>> md.to_datetime('13000101', format='%Y%m%d', errors='ignore').execute() datetime.datetime(1300, 1, 1, 0, 0) >>> md.to_datetime('13000101', format='%Y%m%d', errors='coerce').execute() NaT Passing infer_datetime_format=True can often-times speedup a parsing if its not an ISO8601 format exactly, but in a regular format. >>> s = md.Series(['3/11/2000', '3/12/2000', '3/13/2000'] * 1000) >>> s.head().execute() 0 3/11/2000 1 3/12/2000 2 3/13/2000 3 3/11/2000 4 3/12/2000 dtype: object Using a unix epoch time >>> md.to_datetime(1490195805, unit='s').execute() Timestamp('2017-03-22 15:16:45') >>> md.to_datetime(1490195805433502912, unit='ns').execute() Timestamp('2017-03-22 15:16:45.433502912') .. warning:: For float arg, precision rounding might happen. To prevent unexpected behavior use a fixed-width exact type. Using a non-unix epoch origin >>> md.to_datetime([1, 2, 3], unit='D', ... origin=md.Timestamp('1960-01-01')).execute() DatetimeIndex(['1960-01-02', '1960-01-03', '1960-01-04'], \ dtype='datetime64[ns]', freq=None) """ op = DataFrameToDatetime( errors=errors, dayfirst=dayfirst, yearfirst=yearfirst, utc=utc, format=format, exact=exact, unit=unit, infer_datetime_format=infer_datetime_format, origin=origin, cache=cache, ) return op(arg)