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BUG: Fix date format identification for dict #51479

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merged 3 commits into from
Feb 19, 2023
Merged

BUG: Fix date format identification for dict #51479

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e082f6d
BUG: Fix date format identification for dict
phofl Feb 18, 2023
1ebb836
Cleanup docs
phofl Feb 18, 2023
38895e0
Cleanup docs
phofl Feb 18, 2023
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12 changes: 9 additions & 3 deletions pandas/io/parsers/base_parser.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1244,7 +1244,11 @@ def _isindex(colspec):
raise ValueError(f"Date column {new_name} already in dict")

_, col, old_names = _try_convert_dates(
converter, colspec, data_dict, orig_names
converter,
colspec,
data_dict,
orig_names,
target_name=new_name,
)

new_data[new_name] = col
Expand All @@ -1268,7 +1272,9 @@ def _isindex(colspec):
return data_dict, new_cols


def _try_convert_dates(parser: Callable, colspec, data_dict, columns):
def _try_convert_dates(
parser: Callable, colspec, data_dict, columns, target_name: str | None = None
):
colset = set(columns)
colnames = []

Expand All @@ -1287,7 +1293,7 @@ def _try_convert_dates(parser: Callable, colspec, data_dict, columns):
new_name = "_".join([str(x) for x in colnames])
to_parse = [np.asarray(data_dict[c]) for c in colnames if c in data_dict]

new_col = parser(*to_parse, col=new_name)
new_col = parser(*to_parse, col=new_name if target_name is None else target_name)
return new_name, new_col, colnames


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6 changes: 3 additions & 3 deletions pandas/io/parsers/readers.py
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Expand Up @@ -262,9 +262,9 @@
more strings (corresponding to the columns defined by `parse_dates`) as
arguments.

.. deprecated:: 2.0.0
Use ``date_format`` instead, or read in as ``object`` and then apply
:func:`to_datetime` as-needed.
.. deprecated:: 2.0.0
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This is not rendering properly: https://pandas.pydata.org/docs/dev/reference/api/pandas.read_csv.html

Use ``date_format`` instead, or read in as ``object`` and then apply
:func:`to_datetime` as-needed.
date_format : str or dict of column -> format, default ``None``
If used in conjunction with ``parse_dates``, will parse dates according to this
format. For anything more complex,
Expand Down
7 changes: 4 additions & 3 deletions pandas/tests/io/parser/test_parse_dates.py
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Expand Up @@ -2189,9 +2189,10 @@ def test_parse_dates_dict_format_two_columns(all_parsers, key, parse_dates):
31-,12-2019
31-,12-2020"""

result = parser.read_csv(
StringIO(data), date_format={key: "%d- %m-%Y"}, parse_dates=parse_dates
)
with tm.assert_produces_warning(None):
result = parser.read_csv(
StringIO(data), date_format={key: "%d- %m-%Y"}, parse_dates=parse_dates
)
expected = DataFrame(
{
key: [Timestamp("2019-12-31"), Timestamp("2020-12-31")],
Expand Down