Answers for "introduce a - to a date column in pandas"

convert column in pandas to datetime

df['col'] = pd.to_datetime(df['col'])

convert column series to datetime in pandas dataframe

#Converting column to datetime dtype while loading file.

#Create a date parser function
d_parser = lambda x: pd.to_datetime(x) 
df = pd.read_csv(file_name.csv, parse_dates=['date_column'], date_parser=d_parser)

#If date is not in parseable format, use
pd.to_datetime.strptime(x, format)
#Eg. format for '2017-03-13 04-PM' is '%Y-%M-%D %I-%p'
#Datetime Formatting Codes - http://bit.ly/python-dt-fmt