在数据框中的几列中更改数据时间

Question

I'm trying to change the datatime format of several columns in my dataset however I get:

ValueError: to assemble mappings requires at least that [year, month, day] be specified: [day,month,year] is missing

I'm not sure why as it works if I run the code for each column individually.

from datetime import datetime


df[['last_pymnt_d', 
   'next_pymnt_d', 
   'last_credit_pull_d', 
   'hardship_start_date', 
   'hardship_end_date', 
   'debt_settlement_flag_date',
   'settlement_date', 'issue_d',
   'earliest_cr_line'

  ]] = pd.to_datetime(df[['last_pymnt_d',
                        'next_pymnt_d',
                        'last_credit_pull_d', 
                        'hardship_start_date', 
                        'hardship_end_date', 
                       'debt_settlement_flag_date',
                       'settlement_date', 'issue_d',
                       'earliest_cr_line']], format= '%b-%Y')

Answer 1

You need call function to_datetime to each column separately, so use DataFrame.apply :

cols= ['last_pymnt_d', 
       'next_pymnt_d', 
       'last_credit_pull_d', 
       'hardship_start_date', 
       'hardship_end_date', 
       'debt_settlement_flag_date',
       'settlement_date', 'issue_d',
       'earliest_cr_line']

df[cols] = df[cols].apply(pd.to_datetime)