strftime()

Date and time formatting is important.
strftime – Method to create a string from a datetime.
It takes a datetime, returns a string.

>>> import datetime
>>> now = datetime.datetime.now()
>> now
datetime.datetime(2017, 4, 17, 17, 53, 12, 223121)
>>> # This doesn't look good.....

strftime will help make our output datetimes look pretty.

>>> now.strftime('%B %d')
'April 17'

>>> now.strftime('%m/%d/%y')
'04/17/17'

You don’t have to memorize all these directive symbols.
Get them from their sources:

• https://docs.python.org/3/library/datetime.html
• strftime.org

strptime()

strptime – Method to create a datetime from a string according to a format string.
It takes a string, returns a datetime.

>>> birthday = datetime.datetime.strptime('2015-04-21', '%Y-%m-%d')
>>> birthday
datetime.datetime(2015, 4, 21, 0, 0)

>>> birthday_party = datetime.datetime.strptime('2015-04-21 12:00', '%Y-%m-%d %H:%M')
>>> birthday_party
datetime.datetime(2015, 4, 21, 12, 0)

Remember

strftime is a string from time. strptime is a string parsed into time.

Exercise: from & to

Create a function named to_string that takes a datetime and gives back a string in the format "24 September 2012".
Then, create a new function named from_string that takes two arguments: a date as a string and an strftime-compatible format string, and returns a datetime created from them.

## Examples
# to_string(datetime_object) => "24 September 2012"
# from_string("09/24/12 18:30", "%m/%d/%y %H:%M") => datetime

def to_string(my_datetime):
    return my_datetime.strftime('%d %B %Y')

def from_string(datetime_str, datetime_format):
    return datetime.datetime.strptime(datetime_str, datetime_format)