Trying to get the time delta between two date columns in a dataframe, where one column can possibly be “NaT”

问题

I am trying to get the difference in days between two dates pulled from a SQL database. One is the start date, the other is a completed date. The completed date can and is, in this case, be a NaT value. Essentially I'd like to iterate through each row, and take the difference, if the completed date is NaT I'd like to skip it or assign a NaN value, in a completely new delta column. the code below is giving me this error: 'member_descriptor' object is not callable

for n in df.FINAL_DATE:
  df.DELTA = [0]
  if n is None:
    df.DELTA = None
    break
  else:
    df.DELTA = datetime.timedelta.days(df['FINAL_DATE'], df['START_DATE'])

回答1:

So, you first have to check if any of the dates are NaT. If not, you can calculate by:

df.DELTA = (df['FINAL_DATE'] -  df['START_DATE']).days

来源：https://stackoverflow.com/questions/48647089/trying-to-get-the-time-delta-between-two-date-columns-in-a-dataframe-where-one