Pandas - Python - how to subtract two different date columns

问题

Trying to have a column be filled with today's date minus the created_date column, but getting the following error : TypeError: unsupported operand type(s) for -: 'str' and 'str'

import datetime
now = datetime.date.today()
today = '{0:%m/%d/%Y}'.format(now).format(now)
today
data['Aging'] = today
data['Aging'] = data['Aging'].sub(data['Created_Date'], axis=0)

TypeError: unsupported operand type(s) for -: 'str' and 'str'

回答1:

I think need subtract datetimes, so is necessary convert date in now and in Created_Date column, last for convert timedeltas to days use dt.days:

import datetime
now = datetime.date.today()
today = pd.Timestamp(now)

data['Created_Date'] = pd.to_datetime(data['Created_Date'])
data['Aging'] = today
data['Aging'] = data['Aging'].sub(data['Created_Date'], axis=0).dt.days

Solution should be simplify:

data['Created_Date'] = pd.to_datetime(data['Created_Date'])
data['Aging'] = data['Created_Date'].rsub(today, axis=0).dt.days

回答2:

Maybe, try this as the full code:

data['Created_Date'] = pd.to_datetime(data['Created_Date'])
data['Aging'] = pd.to_datetime('now')
data['Aging'] = data['Aging'].sub(data['Created_Date'], axis=0)

What you want, maybe:

data['Created_Date'] = pd.to_datetime(data['Created_Date'])
data['Aging'] = pd.to_datetime('now').strftime('%m/%d/%Y')
data['Aging'] = data['Aging'].sub(data['Created_Date'], axis=0)

来源：https://stackoverflow.com/questions/51646101/pandas-python-how-to-subtract-two-different-date-columns