Added improvements in to_datetime Error reporting message - incorrect field today/now shown in error (#47860)

* Revert "addressing reviews CL#1" This reverts commit 69dc2d4. * Added improvements in to_datetime Error reporting message - incorrect field now/today shown as error * Added improvements in to_datetime Error reporting message - incorrect field now/today shown as error * added testcase * adding position info & updated testcase * precommit format changes * addressing review comments * addressing review comments * addressing review comments * addressing review comments * addressing review comments #2 * addressing review comments

Author: dannyi96

pandas/_libs/tslib.pyx

@@ -799,6 +799,7 @@ cdef _array_to_datetime_object(
  # We return an object array and only attempt to parse:
  # 1) NaT or NaT-like values
  # 2) datetime strings, which we return as datetime.datetime
+ # 3) special strings - "now" & "today"
  for i in range(n):
  val = values[i]
  if checknull_with_nat_and_na(val) or PyDateTime_Check(val):
@@ -817,7 +818,8 @@ cdef _array_to_datetime_object(
  yearfirst=yearfirst)
  pydatetime_to_dt64(oresult[i], &dts)
  check_dts_bounds(&dts)
- except (ValueError, OverflowError):
+ except (ValueError, OverflowError) as ex:
+ ex.args = (f"{ex} present at position {i}", )
  if is_coerce:
  oresult[i] = <object>NaT
  continue

pandas/_libs/tslibs/parsing.pyx

@@ -298,6 +298,14 @@ def parse_datetime_string(
  if dt is not None:
  return dt
 
+ # Handling special case strings today & now
+ if date_string == "now":
+ dt = datetime.now()
+ return dt
+ elif date_string == "today":
+ dt = datetime.today()
+ return dt
+
  try:
  dt, _ = _parse_dateabbr_string(date_string, _DEFAULT_DATETIME, freq=None)
  return dt

pandas/tests/tools/test_to_datetime.py

@@ -2591,6 +2591,13 @@ def test_invalid_origins_tzinfo(self):
  with pytest.raises(ValueError, match="must be tz-naive"):
  to_datetime(1, unit="D", origin=datetime(2000, 1, 1, tzinfo=pytz.utc))
 
+ def test_incorrect_value_exception(self):
+ # GH47495
+ with pytest.raises(
+ ValueError, match="Unknown string format: yesterday present at position 1"
+ ):
+ to_datetime(["today", "yesterday"])
+
  @pytest.mark.parametrize("format", [None, "%Y-%m-%d %H:%M:%S"])
  def test_to_datetime_out_of_bounds_with_format_arg(self, format):
  # see gh-23830