When I want to convert a column of dates in the data frame into the date format of panda, I encountered this kind of error.

reader = pd.read_csv(f'new_files/2020-12-22-5-10.csv', usecols=['passCarTime'],dtype={'passCarTime':'string'})
pd.to_datetime(reader.passCarTime.head())
Out[98]: 
0   2020-12-22 10:00:00
1   2020-12-22 10:00:00
2   2020-12-22 10:00:00
3   2020-12-22 10:00:00
4   2020-12-22 10:00:00
Name: passCarTime, dtype: datetime64[ns]
pd.to_datetime(reader.passCarTime)
Traceback (most recent call last):
  File "D:\PyCharm2020\python2020\lib\site-packages\pandas\core\arrays\datetimes.py", line 2085, in objects_to_datetime64ns
    values, tz_parsed = conversion.datetime_to_datetime64(data)
  File "pandas\_libs\tslibs\conversion.pyx", line 350, in pandas._libs.tslibs.conversion.datetime_to_datetime64
TypeError: Unrecognized value type: <class 'str'>
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "D:\PyCharm2020\python2020\lib\site-packages\IPython\core\interactiveshell.py", line 3427, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-99-e1b00dc18517>", line 1, in <module>
    pd.to_datetime(reader.passCarTime)
  File "D:\PyCharm2020\python2020\lib\site-packages\pandas\core\tools\datetimes.py", line 801, in to_datetime
    cache_array = _maybe_cache(arg, format, cache, convert_listlike)
  File "D:\PyCharm2020\python2020\lib\site-packages\pandas\core\tools\datetimes.py", line 178, in _maybe_cache
    cache_dates = convert_listlike(unique_dates, format)
  File "D:\PyCharm2020\python2020\lib\site-packages\pandas\core\tools\datetimes.py", line 465, in _convert_listlike_datetimes
    result, tz_parsed = objects_to_datetime64ns(
  File "D:\PyCharm2020\python2020\lib\site-packages\pandas\core\arrays\datetimes.py", line 2090, in objects_to_datetime64ns
    raise e
  File "D:\PyCharm2020\python2020\lib\site-packages\pandas\core\arrays\datetimes.py", line 2075, in objects_to_datetime64ns
    result, tz_parsed = tslib.array_to_datetime(
  File "pandas\_libs\tslib.pyx", line 364, in pandas._libs.tslib.array_to_datetime
  File "pandas\_libs\tslib.pyx", line 591, in pandas._libs.tslib.array_to_datetime
  File "pandas\_libs\tslib.pyx", line 726, in pandas._libs.tslib.array_to_datetime_object
  File "pandas\_libs\tslib.pyx", line 717, in pandas._libs.tslib.array_to_datetime_object
  File "pandas\_libs\tslibs\parsing.pyx", line 243, in pandas._libs.tslibs.parsing.parse_datetime_string
  File "D:\PyCharm2020\python2020\lib\site-packages\dateutil\parser\_parser.py", line 1374, in parse
    return DEFAULTPARSER.parse(timestr, **kwargs)
  File "D:\PyCharm2020\python2020\lib\site-packages\dateutil\parser\_parser.py", line 649, in parse
    raise ParserError("Unknown string format: %s", timestr)
dateutil.parser._parser.ParserError: Unknown string format: passCarTime

I’m not a professional, and my English is not good. I can’t understand what’s wrong. I have seen that there is no missing value in the date column of the file, and there is no date that does not conform to the format… This is very strange, welcome to leave a message, thanks in advance!

Solution

When converting, add a parameter errors ='coerce '.

reader = pd.read_csv(f'new_files/2020-12-22-5-10.csv', usecols=['passCarTime'],dtype={'passCarTime':'string'})
reader.passCarTime = pd.to_datetime(reader.passCarTime,errors='coerce') 
reader.passCarTime.head()
Out[120]: 
0   2020-12-22 10:00:00
1   2020-12-22 10:00:00
2   2020-12-22 10:00:00
3   2020-12-22 10:00:00
4   2020-12-22 10:00:00
Name: passCarTime, dtype: datetime64[ns]
reader.info()
<class 'pandas.core.frame.DataFrame'>
RangeIndex: 307707 entries, 0 to 307706
Data columns (total 1 columns):
 #   Column       Non-Null Count   Dtype         
---  ------       --------------   -----         
 0   passCarTime  307703 non-null  datetime64[ns]
dtypes: datetime64[ns](1)
memory usage: 2.3 MB