I have columns in DataFrame which consist mainly of dates. But there may also be strings or empty values. I want to extract the year from the column but get an error because of string values. Is there a way to apply universal solutions to that? Not only to get a year or month but also to apply other functions which could end with this error. I mean, I would like to understand the nature of this problem and how to deal with it.

code is like

dates={'date':['11/03/2019','12/05/2021','','11/03/2021','x'],
      'date2':['11/04/2019','12/03/2021','11/06/2021',np.nan,'ab'],
}
df2=pd.DataFrame(dates)
df2['year'] =pd.DatetimeIndex(df2['date']).year
the error messages

Unknown string format: x

Thank you in advance!

CodePudding user response：

You can try this,

dates={'date':['11/03/2019','12/05/2021','','11/03/2021','x'],
      'date2':['11/04/2019','12/03/2021','11/06/2021',np.nan,'ab'],
}
df =pd.DataFrame(dates)
df["date"] = pd.to_datetime(df['date'], errors = "coerce")
df["date2"] = pd.to_datetime(df['date2'], errors = "coerce")

df["year1"] = df["date"].dt.year
df["year2"] = df["date2"].dt.year

Output -

If you don't want any null values in your dataframe, do df.dropna(inplace = True) before adding the year1 and year2 columns.