103 lines
3.9 KiB
Python
103 lines
3.9 KiB
Python
from __future__ import annotations
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import string
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from typing import TYPE_CHECKING
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import pyarrow as pa
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import pyarrow.compute as pc
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from narwhals._arrow.utils import ArrowSeriesNamespace, lit, parse_datetime_format
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if TYPE_CHECKING:
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from narwhals._arrow.series import ArrowSeries
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from narwhals._arrow.typing import Incomplete
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class ArrowSeriesStringNamespace(ArrowSeriesNamespace):
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def len_chars(self) -> ArrowSeries:
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return self.with_native(pc.utf8_length(self.native))
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def replace(self, pattern: str, value: str, *, literal: bool, n: int) -> ArrowSeries:
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fn = pc.replace_substring if literal else pc.replace_substring_regex
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arr = fn(self.native, pattern, replacement=value, max_replacements=n)
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return self.with_native(arr)
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def replace_all(self, pattern: str, value: str, *, literal: bool) -> ArrowSeries:
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return self.replace(pattern, value, literal=literal, n=-1)
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def strip_chars(self, characters: str | None) -> ArrowSeries:
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return self.with_native(
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pc.utf8_trim(self.native, characters or string.whitespace)
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)
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def starts_with(self, prefix: str) -> ArrowSeries:
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return self.with_native(pc.equal(self.slice(0, len(prefix)).native, lit(prefix)))
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def ends_with(self, suffix: str) -> ArrowSeries:
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return self.with_native(
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pc.equal(self.slice(-len(suffix), None).native, lit(suffix))
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)
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def contains(self, pattern: str, *, literal: bool) -> ArrowSeries:
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check_func = pc.match_substring if literal else pc.match_substring_regex
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return self.with_native(check_func(self.native, pattern))
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def slice(self, offset: int, length: int | None) -> ArrowSeries:
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stop = offset + length if length is not None else None
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return self.with_native(
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pc.utf8_slice_codeunits(self.native, start=offset, stop=stop)
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)
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def split(self, by: str) -> ArrowSeries:
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split_series = pc.split_pattern(self.native, by) # type: ignore[call-overload]
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return self.with_native(split_series)
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def to_datetime(self, format: str | None) -> ArrowSeries:
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format = parse_datetime_format(self.native) if format is None else format
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timestamp_array = pc.strptime(self.native, format=format, unit="us")
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return self.with_native(timestamp_array)
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def to_date(self, format: str | None) -> ArrowSeries:
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return self.to_datetime(format=format).dt.date()
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def to_uppercase(self) -> ArrowSeries:
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return self.with_native(pc.utf8_upper(self.native))
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def to_lowercase(self) -> ArrowSeries:
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return self.with_native(pc.utf8_lower(self.native))
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def zfill(self, width: int) -> ArrowSeries:
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binary_join: Incomplete = pc.binary_join_element_wise
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native = self.native
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hyphen, plus = lit("-"), lit("+")
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first_char, remaining_chars = (
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self.slice(0, 1).native,
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self.slice(1, None).native,
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)
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# Conditions
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less_than_width = pc.less(pc.utf8_length(native), lit(width))
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starts_with_hyphen = pc.equal(first_char, hyphen)
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starts_with_plus = pc.equal(first_char, plus)
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conditions = pc.make_struct(
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pc.and_(starts_with_hyphen, less_than_width),
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pc.and_(starts_with_plus, less_than_width),
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less_than_width,
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)
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# Cases
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padded_remaining_chars = pc.utf8_lpad(remaining_chars, width - 1, padding="0")
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result = pc.case_when(
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conditions,
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binary_join(
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pa.repeat(hyphen, len(native)), padded_remaining_chars, ""
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), # starts with hyphen and less than width
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binary_join(
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pa.repeat(plus, len(native)), padded_remaining_chars, ""
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), # starts with plus and less than width
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pc.utf8_lpad(native, width=width, padding="0"), # less than width
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native,
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)
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return self.with_native(result)
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