캐글 ​data_cleaning/03-parsing-dates

date_format = '%m/%d/%Y'
earthquakes.loc[indices,'Date'] = pd.to_datetime(earthquakes.loc[indices,'Date']) \
                                   .dt.strftime(date_format)
earthquakes['date_parsed'] = pd.to_datetime(earthquakes['Date'])​​

day_of_month_earthquakes = earthquakes['date_parsed'].dt.day

date_lengths = earthquakes.Date.str.len()
date_lengths.value_counts()