""" Constructor functions intended to be shared by pd.array, Series.__init__, and Index.__new__. These should not depend on core.internals. """ from __future__ import annotations from collections.abc import Sequence from typing import ( TYPE_CHECKING, Optional, Union, cast, overload, ) import warnings import numpy as np from numpy import ma from pandas._config import using_pyarrow_string_dtype from pandas._libs import lib from pandas._libs.tslibs import ( Period, get_supported_dtype, is_supported_dtype, ) from pandas._typing import ( AnyArrayLike, ArrayLike, Dtype, DtypeObj, T, ) from pandas.util._exceptions import find_stack_level from pandas.core.dtypes.base import ExtensionDtype from pandas.core.dtypes.cast import ( construct_1d_arraylike_from_scalar, construct_1d_object_array_from_listlike, maybe_cast_to_datetime, maybe_cast_to_integer_array, maybe_convert_platform, maybe_infer_to_datetimelike, maybe_promote, ) from pandas.core.dtypes.common import ( is_list_like, is_object_dtype, is_string_dtype, pandas_dtype, ) from pandas.core.dtypes.dtypes import NumpyEADtype from pandas.core.dtypes.generic import ( ABCDataFrame, ABCExtensionArray, ABCIndex, ABCSeries, ) from pandas.core.dtypes.missing import isna import pandas.core.common as com if TYPE_CHECKING: from pandas import ( Index, Series, ) from pandas.core.arrays.base import ExtensionArray def array( data: Sequence[object] | AnyArrayLike, dtype: Dtype | None = None, copy: bool = True, ) -> ExtensionArray: """ Create an array. Parameters ---------- data : Sequence of objects The scalars inside `data` should be instances of the scalar type for `dtype`. It's expected that `data` represents a 1-dimensional array of data. When `data` is an Index or Series, the underlying array will be extracted from `data`. dtype : str, np.dtype, or ExtensionDtype, optional The dtype to use for the array. This may be a NumPy dtype or an extension type registered with pandas using :meth:`pandas.api.extensions.register_extension_dtype`. If not specified, there are two possibilities: 1. When `data` is a :class:`Series`, :class:`Index`, or :class:`ExtensionArray`, the `dtype` will be taken from the data. 2. Otherwise, pandas will attempt to infer the `dtype` from the data. Note that when `data` is a NumPy array, ``data.dtype`` is *not* used for inferring the array type. This is because NumPy cannot represent all the types of data that can be held in extension arrays. Currently, pandas will infer an extension dtype for sequences of ============================== ======================================= Scalar Type Array Type ============================== ======================================= :class:`pandas.Interval` :class:`pandas.arrays.IntervalArray` :class:`pandas.Period` :class:`pandas.arrays.PeriodArray` :class:`datetime.datetime` :class:`pandas.arrays.DatetimeArray` :class:`datetime.timedelta` :class:`pandas.arrays.TimedeltaArray` :class:`int` :class:`pandas.arrays.IntegerArray` :class:`float` :class:`pandas.arrays.FloatingArray` :class:`str` :class:`pandas.arrays.StringArray` or :class:`pandas.arrays.ArrowStringArray` :class:`bool` :class:`pandas.arrays.BooleanArray` ============================== ======================================= The ExtensionArray created when the scalar type is :class:`str` is determined by ``pd.options.mode.string_storage`` if the dtype is not explicitly given. For all other cases, NumPy's usual inference rules will be used. copy : bool, default True Whether to copy the data, even if not necessary. Depending on the type of `data`, creating the new array may require copying data, even if ``copy=False``. Returns ------- ExtensionArray The newly created array. Raises ------ ValueError When `data` is not 1-dimensional. See Also -------- numpy.array : Construct a NumPy array. Series : Construct a pandas Series. Index : Construct a pandas Index. arrays.NumpyExtensionArray : ExtensionArray wrapping a NumPy array. Series.array : Extract the array stored within a Series. Notes ----- Omitting the `dtype` argument means pandas will attempt to infer the best array type from the values in the data. As new array types are added by pandas and 3rd party libraries, the "best" array type may change. We recommend specifying `dtype` to ensure that 1. the correct array type for the data is returned 2. the returned array type doesn't change as new extension types are added by pandas and third-party libraries Additionally, if the underlying memory representation of the returned array matters, we recommend specifying the `dtype` as a concrete object rather than a string alias or allowing it to be inferred. For example, a future version of pandas or a 3rd-party library may include a dedicated ExtensionArray for string data. In this event, the following would no longer return a :class:`arrays.NumpyExtensionArray` backed by a NumPy array. >>> pd.array(['a', 'b'], dtype=str) ['a', 'b'] Length: 2, dtype: str32 This would instead return the new ExtensionArray dedicated for string data. If you really need the new array to be backed by a NumPy array, specify that in the dtype. >>> pd.array(['a', 'b'], dtype=np.dtype(" ['a', 'b'] Length: 2, dtype: str32 Finally, Pandas has arrays that mostly overlap with NumPy * :class:`arrays.DatetimeArray` * :class:`arrays.TimedeltaArray` When data with a ``datetime64[ns]`` or ``timedelta64[ns]`` dtype is passed, pandas will always return a ``DatetimeArray`` or ``TimedeltaArray`` rather than a ``NumpyExtensionArray``. This is for symmetry with the case of timezone-aware data, which NumPy does not natively support. >>> pd.array(['2015', '2016'], dtype='datetime64[ns]') ['2015-01-01 00:00:00', '2016-01-01 00:00:00'] Length: 2, dtype: datetime64[ns] >>> pd.array(["1h", "2h"], dtype='timedelta64[ns]') ['0 days 01:00:00', '0 days 02:00:00'] Length: 2, dtype: timedelta64[ns] Examples -------- If a dtype is not specified, pandas will infer the best dtype from the values. See the description of `dtype` for the types pandas infers for. >>> pd.array([1, 2]) [1, 2] Length: 2, dtype: Int64 >>> pd.array([1, 2, np.nan]) [1, 2, ] Length: 3, dtype: Int64 >>> pd.array([1.1, 2.2]) [1.1, 2.2] Length: 2, dtype: Float64 >>> pd.array(["a", None, "c"]) ['a', , 'c'] Length: 3, dtype: string >>> with pd.option_context("string_storage", "pyarrow"): ... arr = pd.array(["a", None, "c"]) ... >>> arr ['a', , 'c'] Length: 3, dtype: string >>> pd.array([pd.Period('2000', freq="D"), pd.Period("2000", freq="D")]) ['2000-01-01', '2000-01-01'] Length: 2, dtype: period[D] You can use the string alias for `dtype` >>> pd.array(['a', 'b', 'a'], dtype='category') ['a', 'b', 'a'] Categories (2, object): ['a', 'b'] Or specify the actual dtype >>> pd.array(['a', 'b', 'a'], ... dtype=pd.CategoricalDtype(['a', 'b', 'c'], ordered=True)) ['a', 'b', 'a'] Categories (3, object): ['a' < 'b' < 'c'] If pandas does not infer a dedicated extension type a :class:`arrays.NumpyExtensionArray` is returned. >>> pd.array([1 + 1j, 3 + 2j]) [(1+1j), (3+2j)] Length: 2, dtype: complex128 As mentioned in the "Notes" section, new extension types may be added in the future (by pandas or 3rd party libraries), causing the return value to no longer be a :class:`arrays.NumpyExtensionArray`. Specify the `dtype` as a NumPy dtype if you need to ensure there's no future change in behavior. >>> pd.array([1, 2], dtype=np.dtype("int32")) [1, 2] Length: 2, dtype: int32 `data` must be 1-dimensional. A ValueError is raised when the input has the wrong dimensionality. >>> pd.array(1) Traceback (most recent call last): ... ValueError: Cannot pass scalar '1' to 'pandas.array'. """ from pandas.core.arrays import ( BooleanArray, DatetimeArray, ExtensionArray, FloatingArray, IntegerArray, IntervalArray, NumpyExtensionArray, PeriodArray, TimedeltaArray, ) from pandas.core.arrays.string_ import StringDtype if lib.is_scalar(data): msg = f"Cannot pass scalar '{data}' to 'pandas.array'." raise ValueError(msg) elif isinstance(data, ABCDataFrame): raise TypeError("Cannot pass DataFrame to 'pandas.array'") if dtype is None and isinstance(data, (ABCSeries, ABCIndex, ExtensionArray)): # Note: we exclude np.ndarray here, will do type inference on it dtype = data.dtype data = extract_array(data, extract_numpy=True) # this returns None for not-found dtypes. if dtype is not None: dtype = pandas_dtype(dtype) if isinstance(data, ExtensionArray) and (dtype is None or data.dtype == dtype): # e.g. TimedeltaArray[s], avoid casting to NumpyExtensionArray if copy: return data.copy() return data if isinstance(dtype, ExtensionDtype): cls = dtype.construct_array_type() return cls._from_sequence(data, dtype=dtype, copy=copy) if dtype is None: inferred_dtype = lib.infer_dtype(data, skipna=True) if inferred_dtype == "period": period_data = cast(Union[Sequence[Optional[Period]], AnyArrayLike], data) return PeriodArray._from_sequence(period_data, copy=copy) elif inferred_dtype == "interval": return IntervalArray(data, copy=copy) elif inferred_dtype.startswith("datetime"): # datetime, datetime64 try: return DatetimeArray._from_sequence(data, copy=copy) except ValueError: # Mixture of timezones, fall back to NumpyExtensionArray pass elif inferred_dtype.startswith("timedelta"): # timedelta, timedelta64 return TimedeltaArray._from_sequence(data, copy=copy) elif inferred_dtype == "string": # StringArray/ArrowStringArray depending on pd.options.mode.string_storage dtype = StringDtype() cls = dtype.construct_array_type() return cls._from_sequence(data, dtype=dtype, copy=copy) elif inferred_dtype == "integer": return IntegerArray._from_sequence(data, copy=copy) elif inferred_dtype == "empty" and not hasattr(data, "dtype") and not len(data): return FloatingArray._from_sequence(data, copy=copy) elif ( inferred_dtype in ("floating", "mixed-integer-float") and getattr(data, "dtype", None) != np.float16 ): # GH#44715 Exclude np.float16 bc FloatingArray does not support it; # we will fall back to NumpyExtensionArray. return FloatingArray._from_sequence(data, copy=copy) elif inferred_dtype == "boolean": return BooleanArray._from_sequence(data, dtype="boolean", copy=copy) # Pandas overrides NumPy for # 1. datetime64[ns,us,ms,s] # 2. timedelta64[ns,us,ms,s] # so that a DatetimeArray is returned. if lib.is_np_dtype(dtype, "M") and is_supported_dtype(dtype): return DatetimeArray._from_sequence(data, dtype=dtype, copy=copy) if lib.is_np_dtype(dtype, "m") and is_supported_dtype(dtype): return TimedeltaArray._from_sequence(data, dtype=dtype, copy=copy) elif lib.is_np_dtype(dtype, "mM"): warnings.warn( r"datetime64 and timedelta64 dtype resolutions other than " r"'s', 'ms', 'us', and 'ns' are deprecated. " r"In future releases passing unsupported resolutions will " r"raise an exception.", FutureWarning, stacklevel=find_stack_level(), ) return NumpyExtensionArray._from_sequence(data, dtype=dtype, copy=copy) _typs = frozenset( { "index", "rangeindex", "multiindex", "datetimeindex", "timedeltaindex", "periodindex", "categoricalindex", "intervalindex", "series", } ) @overload def extract_array( obj: Series | Index, extract_numpy: bool = ..., extract_range: bool = ... ) -> ArrayLike: ... @overload def extract_array( obj: T, extract_numpy: bool = ..., extract_range: bool = ... ) -> T | ArrayLike: ... def extract_array( obj: T, extract_numpy: bool = False, extract_range: bool = False ) -> T | ArrayLike: """ Extract the ndarray or ExtensionArray from a Series or Index. For all other types, `obj` is just returned as is. Parameters ---------- obj : object For Series / Index, the underlying ExtensionArray is unboxed. extract_numpy : bool, default False Whether to extract the ndarray from a NumpyExtensionArray. extract_range : bool, default False If we have a RangeIndex, return range._values if True (which is a materialized integer ndarray), otherwise return unchanged. Returns ------- arr : object Examples -------- >>> extract_array(pd.Series(['a', 'b', 'c'], dtype='category')) ['a', 'b', 'c'] Categories (3, object): ['a', 'b', 'c'] Other objects like lists, arrays, and DataFrames are just passed through. >>> extract_array([1, 2, 3]) [1, 2, 3] For an ndarray-backed Series / Index the ndarray is returned. >>> extract_array(pd.Series([1, 2, 3])) array([1, 2, 3]) To extract all the way down to the ndarray, pass ``extract_numpy=True``. >>> extract_array(pd.Series([1, 2, 3]), extract_numpy=True) array([1, 2, 3]) """ typ = getattr(obj, "_typ", None) if typ in _typs: # i.e. isinstance(obj, (ABCIndex, ABCSeries)) if typ == "rangeindex": if extract_range: # error: "T" has no attribute "_values" return obj._values # type: ignore[attr-defined] return obj # error: "T" has no attribute "_values" return obj._values # type: ignore[attr-defined] elif extract_numpy and typ == "npy_extension": # i.e. isinstance(obj, ABCNumpyExtensionArray) # error: "T" has no attribute "to_numpy" return obj.to_numpy() # type: ignore[attr-defined] return obj def ensure_wrapped_if_datetimelike(arr): """ Wrap datetime64 and timedelta64 ndarrays in DatetimeArray/TimedeltaArray. """ if isinstance(arr, np.ndarray): if arr.dtype.kind == "M": from pandas.core.arrays import DatetimeArray dtype = get_supported_dtype(arr.dtype) return DatetimeArray._from_sequence(arr, dtype=dtype) elif arr.dtype.kind == "m": from pandas.core.arrays import TimedeltaArray dtype = get_supported_dtype(arr.dtype) return TimedeltaArray._from_sequence(arr, dtype=dtype) return arr def sanitize_masked_array(data: ma.MaskedArray) -> np.ndarray: """ Convert numpy MaskedArray to ensure mask is softened. """ mask = ma.getmaskarray(data) if mask.any(): dtype, fill_value = maybe_promote(data.dtype, np.nan) dtype = cast(np.dtype, dtype) data = ma.asarray(data.astype(dtype, copy=True)) data.soften_mask() # set hardmask False if it was True data[mask] = fill_value else: data = data.copy() return data def sanitize_array( data, index: Index | None, dtype: DtypeObj | None = None, copy: bool = False, *, allow_2d: bool = False, ) -> ArrayLike: """ Sanitize input data to an ndarray or ExtensionArray, copy if specified, coerce to the dtype if specified. Parameters ---------- data : Any index : Index or None, default None dtype : np.dtype, ExtensionDtype, or None, default None copy : bool, default False allow_2d : bool, default False If False, raise if we have a 2D Arraylike. Returns ------- np.ndarray or ExtensionArray """ original_dtype = dtype if isinstance(data, ma.MaskedArray): data = sanitize_masked_array(data) if isinstance(dtype, NumpyEADtype): # Avoid ending up with a NumpyExtensionArray dtype = dtype.numpy_dtype object_index = False if isinstance(data, ABCIndex) and data.dtype == object and dtype is None: object_index = True # extract ndarray or ExtensionArray, ensure we have no NumpyExtensionArray data = extract_array(data, extract_numpy=True, extract_range=True) if isinstance(data, np.ndarray) and data.ndim == 0: if dtype is None: dtype = data.dtype data = lib.item_from_zerodim(data) elif isinstance(data, range): # GH#16804 data = range_to_ndarray(data) copy = False if not is_list_like(data): if index is None: raise ValueError("index must be specified when data is not list-like") if ( isinstance(data, str) and using_pyarrow_string_dtype() and original_dtype is None ): from pandas.core.arrays.string_ import StringDtype dtype = StringDtype("pyarrow_numpy") data = construct_1d_arraylike_from_scalar(data, len(index), dtype) return data elif isinstance(data, ABCExtensionArray): # it is already ensured above this is not a NumpyExtensionArray # Until GH#49309 is fixed this check needs to come before the # ExtensionDtype check if dtype is not None: subarr = data.astype(dtype, copy=copy) elif copy: subarr = data.copy() else: subarr = data elif isinstance(dtype, ExtensionDtype): # create an extension array from its dtype _sanitize_non_ordered(data) cls = dtype.construct_array_type() subarr = cls._from_sequence(data, dtype=dtype, copy=copy) # GH#846 elif isinstance(data, np.ndarray): if isinstance(data, np.matrix): data = data.A if dtype is None: subarr = data if data.dtype == object: subarr = maybe_infer_to_datetimelike(data) if ( object_index and using_pyarrow_string_dtype() and is_string_dtype(subarr) ): # Avoid inference when string option is set subarr = data elif data.dtype.kind == "U" and using_pyarrow_string_dtype(): from pandas.core.arrays.string_ import StringDtype dtype = StringDtype(storage="pyarrow_numpy") subarr = dtype.construct_array_type()._from_sequence(data, dtype=dtype) if subarr is data and copy: subarr = subarr.copy() else: # we will try to copy by-definition here subarr = _try_cast(data, dtype, copy) elif hasattr(data, "__array__"): # e.g. dask array GH#38645 data = np.array(data, copy=copy) return sanitize_array( data, index=index, dtype=dtype, copy=False, allow_2d=allow_2d, ) else: _sanitize_non_ordered(data) # materialize e.g. generators, convert e.g. tuples, abc.ValueView data = list(data) if len(data) == 0 and dtype is None: # We default to float64, matching numpy subarr = np.array([], dtype=np.float64) elif dtype is not None: subarr = _try_cast(data, dtype, copy) else: subarr = maybe_convert_platform(data) if subarr.dtype == object: subarr = cast(np.ndarray, subarr) subarr = maybe_infer_to_datetimelike(subarr) subarr = _sanitize_ndim(subarr, data, dtype, index, allow_2d=allow_2d) if isinstance(subarr, np.ndarray): # at this point we should have dtype be None or subarr.dtype == dtype dtype = cast(np.dtype, dtype) subarr = _sanitize_str_dtypes(subarr, data, dtype, copy) return subarr def range_to_ndarray(rng: range) -> np.ndarray: """ Cast a range object to ndarray. """ # GH#30171 perf avoid realizing range as a list in np.array try: arr = np.arange(rng.start, rng.stop, rng.step, dtype="int64") except OverflowError: # GH#30173 handling for ranges that overflow int64 if (rng.start >= 0 and rng.step > 0) or (rng.step < 0 <= rng.stop): try: arr = np.arange(rng.start, rng.stop, rng.step, dtype="uint64") except OverflowError: arr = construct_1d_object_array_from_listlike(list(rng)) else: arr = construct_1d_object_array_from_listlike(list(rng)) return arr def _sanitize_non_ordered(data) -> None: """ Raise only for unordered sets, e.g., not for dict_keys """ if isinstance(data, (set, frozenset)): raise TypeError(f"'{type(data).__name__}' type is unordered") def _sanitize_ndim( result: ArrayLike, data, dtype: DtypeObj | None, index: Index | None, *, allow_2d: bool = False, ) -> ArrayLike: """ Ensure we have a 1-dimensional result array. """ if getattr(result, "ndim", 0) == 0: raise ValueError("result should be arraylike with ndim > 0") if result.ndim == 1: # the result that we want result = _maybe_repeat(result, index) elif result.ndim > 1: if isinstance(data, np.ndarray): if allow_2d: return result raise ValueError( f"Data must be 1-dimensional, got ndarray of shape {data.shape} instead" ) if is_object_dtype(dtype) and isinstance(dtype, ExtensionDtype): # i.e. NumpyEADtype("O") result = com.asarray_tuplesafe(data, dtype=np.dtype("object")) cls = dtype.construct_array_type() result = cls._from_sequence(result, dtype=dtype) else: # error: Argument "dtype" to "asarray_tuplesafe" has incompatible type # "Union[dtype[Any], ExtensionDtype, None]"; expected "Union[str, # dtype[Any], None]" result = com.asarray_tuplesafe(data, dtype=dtype) # type: ignore[arg-type] return result def _sanitize_str_dtypes( result: np.ndarray, data, dtype: np.dtype | None, copy: bool ) -> np.ndarray: """ Ensure we have a dtype that is supported by pandas. """ # This is to prevent mixed-type Series getting all casted to # NumPy string type, e.g. NaN --> '-1#IND'. if issubclass(result.dtype.type, str): # GH#16605 # If not empty convert the data to dtype # GH#19853: If data is a scalar, result has already the result if not lib.is_scalar(data): if not np.all(isna(data)): data = np.array(data, dtype=dtype, copy=False) result = np.array(data, dtype=object, copy=copy) return result def _maybe_repeat(arr: ArrayLike, index: Index | None) -> ArrayLike: """ If we have a length-1 array and an index describing how long we expect the result to be, repeat the array. """ if index is not None: if 1 == len(arr) != len(index): arr = arr.repeat(len(index)) return arr def _try_cast( arr: list | np.ndarray, dtype: np.dtype, copy: bool, ) -> ArrayLike: """ Convert input to numpy ndarray and optionally cast to a given dtype. Parameters ---------- arr : ndarray or list Excludes: ExtensionArray, Series, Index. dtype : np.dtype copy : bool If False, don't copy the data if not needed. Returns ------- np.ndarray or ExtensionArray """ is_ndarray = isinstance(arr, np.ndarray) if dtype == object: if not is_ndarray: subarr = construct_1d_object_array_from_listlike(arr) return subarr return ensure_wrapped_if_datetimelike(arr).astype(dtype, copy=copy) elif dtype.kind == "U": # TODO: test cases with arr.dtype.kind in "mM" if is_ndarray: arr = cast(np.ndarray, arr) shape = arr.shape if arr.ndim > 1: arr = arr.ravel() else: shape = (len(arr),) return lib.ensure_string_array(arr, convert_na_value=False, copy=copy).reshape( shape ) elif dtype.kind in "mM": return maybe_cast_to_datetime(arr, dtype) # GH#15832: Check if we are requesting a numeric dtype and # that we can convert the data to the requested dtype. elif dtype.kind in "iu": # this will raise if we have e.g. floats subarr = maybe_cast_to_integer_array(arr, dtype) else: subarr = np.array(arr, dtype=dtype, copy=copy) return subarr