avoiding error from pd.to_datetime in pandas

问题:

I have a huge dataframe more than 100 mln rows. In that I have a date columns, unfortunately have improper formatted (mixed) date strings.

Now I did convert it to datetime by:

df['TRX_DATE'] = pd.to_datetime(df['TRX_DATE'],coerce=True) # without any error # Now i want to calculate week day from that date columns df['day_type'] = [x.strftime('%A') for x in d['TRX_DATE']] ###ValueError: month out of range 

If it would a single field I can manage with dateutil parser. But in this case I am getting out of idea, how to handle that.

Just intersted, if the week conversion line can have something like if anything getting out of range place a default...

Have the idea but as a newbie. Don't have that much experience to do that.

It would be great help if someone can give a code line to handle that.

回答1:

I think you can parse to_datetime with parameter errors='coerce' and then use strftime for converting to weekday as locale’s full name:

print df               TRX_DATE  some value 0  2010-08-15 13:00:00      27.065 1  2010-08-16 13:10:00      25.610 2  2010-08-17 02:30:00      17.000 3  2010-06-18 02:40:00      17.015 4  2010-18-19 02:50:00      16.910  df['TRX_DATE'] = pd.to_datetime(df['TRX_DATE'],errors='coerce')  df['day_type'] = df['TRX_DATE'].dt.strftime('%A') print df              TRX_DATE  some value day_type 0 2010-08-15 13:00:00      27.065   Sunday 1 2010-08-16 13:10:00      25.610   Monday 2 2010-08-17 02:30:00      17.000  Tuesday 3 2010-06-18 02:40:00      17.015   Friday 4                 NaT      16.910      NaT 

回答2:

[x.strftime('%A') for x in df['TRX_DATE'] if not isinstance(x, pandas.tslib.NaTType)] 

文章来源: avoiding error from pd.to_datetime in pandas