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REF: more explicit dtypes in strings.accessor #41727

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Merged
merged 9 commits into from
Jun 9, 2021
Merged

REF: more explicit dtypes in strings.accessor #41727

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d9629d6
REF: more explicit dtypes in strings.accessor
jbrockmendel May 29, 2021
4204274
revert explode edit
jbrockmendel May 30, 2021
20e1388
Merge branch 'master' into ref-string-casting
jbrockmendel May 31, 2021
20919a1
Merge branch 'master' into ref-string-casting
jbrockmendel May 31, 2021
469a517
Merge branch 'master' into ref-string-casting
jbrockmendel Jun 1, 2021
f18ad50
Merge branch 'master' into ref-string-casting
jbrockmendel Jun 1, 2021
2346970
fix test_numpy tests
jbrockmendel Jun 1, 2021
d6542dd
Merge branch 'master' into ref-string-casting
jbrockmendel Jun 7, 2021
8ed20e6
remove returns_bool
jbrockmendel Jun 7, 2021
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38 changes: 25 additions & 13 deletions pandas/core/strings/accessor.py
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,10 @@
import numpy as np

import pandas._libs.lib as lib
from pandas._typing import FrameOrSeriesUnion
from pandas._typing import (
DtypeObj,
FrameOrSeriesUnion,
)
from pandas.util._decorators import Appender

from pandas.core.dtypes.common import (
Expand All @@ -34,6 +37,7 @@
from pandas.core.dtypes.missing import isna

from pandas.core.base import NoNewAttributesMixin
from pandas.core.construction import extract_array

if TYPE_CHECKING:
from pandas import Index
Expand Down Expand Up @@ -122,7 +126,7 @@ def _map_and_wrap(name, docstring):
@forbid_nonstring_types(["bytes"], name=name)
def wrapper(self):
result = getattr(self._data.array, f"_str_{name}")()
return self._wrap_result(result)
return self._wrap_result(result, returns_bool=True)

wrapper.__doc__ = docstring
return wrapper
Expand Down Expand Up @@ -209,8 +213,8 @@ def _validate(data):
# see _libs/lib.pyx for list of inferred types
allowed_types = ["string", "empty", "bytes", "mixed", "mixed-integer"]

values = getattr(data, "values", data) # Series / Index
values = getattr(values, "categories", values) # categorical / normal
data = extract_array(data, extract_numpy=True)
values = getattr(data, "categories", data) # categorical / normal

inferred_dtype = lib.infer_dtype(values, skipna=True)

Expand Down Expand Up @@ -242,6 +246,7 @@ def _wrap_result(
expand: bool | None = None,
fill_value=np.nan,
returns_string=True,
returns_bool: bool = False,
):
from pandas import (
Index,
Expand Down Expand Up @@ -319,19 +324,26 @@ def cons_row(x):
else:
index = self._orig.index
# This is a mess.
dtype: str | None
if self._is_string and returns_string:
dtype = self._orig.dtype
dtype: DtypeObj | str | None
if self._is_string:
if returns_bool:
dtype = "boolean"
elif returns_string:
dtype = self._orig.dtype
else:
dtype = result.dtype
elif returns_bool:
dtype = result.dtype # i.e. bool
else:
dtype = None
dtype = getattr(result, "dtype", None)

if expand:
cons = self._orig._constructor_expanddim
result = cons(result, columns=name, index=index, dtype=dtype)
else:
# Must be a Series
cons = self._orig._constructor
result = cons(result, name=name, index=index)
result = cons(result, name=name, index=index, dtype=dtype)
result = result.__finalize__(self._orig, method="str")
if name is not None and result.ndim == 1:
# __finalize__ might copy over the original name, but we may
Expand Down Expand Up @@ -369,7 +381,7 @@ def _get_series_list(self, others):
if isinstance(others, ABCSeries):
return [others]
elif isinstance(others, ABCIndex):
return [Series(others._values, index=idx)]
return [Series(others._values, index=idx, dtype=others.dtype)]
elif isinstance(others, ABCDataFrame):
return [others[x] for x in others]
elif isinstance(others, np.ndarray) and others.ndim == 2:
Expand Down Expand Up @@ -547,7 +559,7 @@ def cat(self, others=None, sep=None, na_rep=None, join="left"):
sep = ""

if isinstance(self._orig, ABCIndex):
data = Series(self._orig, index=self._orig)
data = Series(self._orig, index=self._orig, dtype=self._orig.dtype)
else: # Series
data = self._orig

Expand Down Expand Up @@ -2145,7 +2157,7 @@ def startswith(self, pat, na=None):
dtype: bool
"""
result = self._data.array._str_startswith(pat, na=na)
return self._wrap_result(result, returns_string=False)
return self._wrap_result(result, returns_string=False, returns_bool=True)
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can we just change _wrap_result so we don't have 2 keywords? maybe rename to returns_dtype and pass a string?

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thats tough bc the end-result dtype depends on self._is_string

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Looking at this again it really doesnt look worth the trouble to try to combine these args

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I don't think either keywords should really be necessary here, the issue is that the arrays passed when expand is True are object arrays of lists/tuples

which method returns bool, where the dtype of the result is not bool?

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which method returns bool, where the dtype of the result is not bool?

makes sense, ill give this a try

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e.g isnumeric we can get object-dtype result of bools and nans

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@simonjayhawkins simonjayhawkins Jun 7, 2021 •
edited
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the wrapped result would be object in this case? This is for a object dtype array? for StringArray/ArrowString array the return type should always be boolean. object dtype accessors do cast their results, except extract, so if the result is all bools and no nans, the result dtype should be np.bool

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the result dtype should be np.bool

the result to be wrapped dtype should be np.bool

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these conversions are handled in _str_map in ObjectStringArrayMixin


@forbid_nonstring_types(["bytes"])
def endswith(self, pat, na=None):
Expand Down Expand Up @@ -2202,7 +2214,7 @@ def endswith(self, pat, na=None):
dtype: bool
"""
result = self._data.array._str_endswith(pat, na=na)
return self._wrap_result(result, returns_string=False)
return self._wrap_result(result, returns_string=False, returns_bool=True)

@forbid_nonstring_types(["bytes"])
def findall(self, pat, flags=0):
Expand Down