BUG: to_datetime with mixed iso-str and ints

[jbrockmendel]

objs = ["2016-01-01 01:02:03+05:00", "2016-01-01 01:02:03+06:00", 0]

pd.to_datetime(objs[::-1])  # <- raises with RuntimeError: No active exception to reraise

pd.to_datetime(objs)  # <- raises ValueError

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "pandas/core/tools/datetimes.py", line 1077, in to_datetime
    result = convert_listlike(argc, format)
  File "pandas/core/tools/datetimes.py", line 449, in _convert_listlike_datetimes
    return _array_strptime_with_fallback(arg, name, utc, format, exact, errors)
  File "pandas/core/tools/datetimes.py", line 480, in _array_strptime_with_fallback
    result, timezones = array_strptime(arg, fmt, exact=exact, errors=errors, utc=utc)
  File "pandas/_libs/tslibs/strptime.pyx", line 513, in pandas._libs.tslibs.strptime.array_strptime
    raise
  File "pandas/_libs/tslibs/strptime.pyx", line 342, in pandas._libs.tslibs.strptime.array_strptime
    raise ValueError(f"time data \"{val}\" doesn't "
ValueError: time data "0" doesn't match format "%Y-%m-%d %H:%M:%S%z", at position 2

cc @MarcoGorelli

[MarcoGorelli]

thanks! will address

---

looks like this was present in 1.5.2 too:

In [1]: to_datetime([0, '2016-01-01 01:02:03+06:00', '2016-01-01 01:02:03+05:00'])
---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
Cell In [1], line 1
----> 1 to_datetime([0, '2016-01-01 01:02:03+06:00', '2016-01-01 01:02:03+05:00'])

File ~/tmp/.venv/lib/python3.8/site-packages/pandas/core/tools/datetimes.py:1100, in to_datetime(arg, errors, dayfirst, yearfirst, utc, format, exact, unit, infer_datetime_format, origin, cache)
   1098         result = _convert_and_box_cache(argc, cache_array)
   1099     else:
-> 1100         result = convert_listlike(argc, format)
   1101 else:
   1102     result = convert_listlike(np.array([arg]), format)[0]

File ~/tmp/.venv/lib/python3.8/site-packages/pandas/core/tools/datetimes.py:438, in _convert_listlike_datetimes(arg, format, name, tz, unit, errors, infer_datetime_format, dayfirst, yearfirst, exact)
    436 assert format is None or infer_datetime_format
    437 utc = tz == "utc"
--> 438 result, tz_parsed = objects_to_datetime64ns(
    439     arg,
    440     dayfirst=dayfirst,
    441     yearfirst=yearfirst,
    442     utc=utc,
    443     errors=errors,
    444     require_iso8601=require_iso8601,
    445     allow_object=True,
    446 )
    448 if tz_parsed is not None:
    449     # We can take a shortcut since the datetime64 numpy array
    450     # is in UTC
    451     dta = DatetimeArray(result, dtype=tz_to_dtype(tz_parsed))

File ~/tmp/.venv/lib/python3.8/site-packages/pandas/core/arrays/datetimes.py:2177, in objects_to_datetime64ns(data, dayfirst, yearfirst, utc, errors, require_iso8601, allow_object, allow_mixed)
   2175 order: Literal["F", "C"] = "F" if flags.f_contiguous else "C"
   2176 try:
-> 2177     result, tz_parsed = tslib.array_to_datetime(
   2178         data.ravel("K"),
   2179         errors=errors,
   2180         utc=utc,
   2181         dayfirst=dayfirst,
   2182         yearfirst=yearfirst,
   2183         require_iso8601=require_iso8601,
   2184         allow_mixed=allow_mixed,
   2185     )
   2186     result = result.reshape(data.shape, order=order)
   2187 except OverflowError as err:
   2188     # Exception is raised when a part of date is greater than 32 bit signed int

File ~/tmp/.venv/lib/python3.8/site-packages/pandas/_libs/tslib.pyx:427, in pandas._libs.tslib.array_to_datetime()

File ~/tmp/.venv/lib/python3.8/site-packages/pandas/_libs/tslib.pyx:711, in pandas._libs.tslib.array_to_datetime()

File ~/tmp/.venv/lib/python3.8/site-packages/pandas/_libs/tslib.pyx:833, in pandas._libs.tslib._array_to_datetime_object()

RuntimeError: No active exception to reraise

In [2]: pd.__version__
Out[2]: '1.5.2'

[jbrockmendel]

If it isn't addressed before then, this will be closeable in 3.0 when the deprecated _array_to_datetime_object path is removed.