Representing time with datetimes

Intermediate Python for Finance

Kennedy Behrman

Data Engineer, Author, Founder

Datetimes

Chart of rising stock price

Datetimes

Chart of Cuban trade deficit

Datetimes

from datetime import datetime

black_monday = datetime(1987, 10, 19)
print(black_monday)

datetime.datetime(1987, 10, 19, 0, 0)

Datetime now

datetime.now()

datetime.datetime(2019, 11, 6, 3, 48, 30, 886713)

Datetime from string

black_monday_str = "Monday, October 19, 1987. 9:30 am"
format_str = "%A, %B %d, %Y. %I:%M %p"
datetime.datetime.strptime(black_monday_str, format_str)

datetime.datetime(1987, 10, 19, 9, 30)

Datetime from string

Year

%y Without century (01, 02, ..., 98, 99)
%Y With century (0001, 0002, ..., 1998, 1999, ..., 9999)

Month

%b Abbreviated names (Jan, Feb, ..., Nov, Dec)
%B Full names (January, February, ... November, December)
%m As numbers (01, 02, ..., 11, 12)

Day of Month

%d (01, 02, ..., 30, 31)

Datetime from string

Weekday

%a Abbreviated name (Sun, ... Sat)
%A Full name (Sunday, ... Saturday)
%w Number (0, ..., 6)

Hour

%H 24 hour (00, 01, ... 23)
%I 12 hour (01, 02, ... 12)
%M (01, 02, ..., 59)

Datetime from string

Seconds

%S (00, 01, ... 59)

Micro-seconds

%f (000000, 000001, ... 999999)

AM/PM

%p (AM, PM)

Datetime from string

%m Months

%M Minutes

Datetime from string

"1837-05-10"

%Y

%m

%d

"%Y-%m-%d"

Datetime from string

"Friday, 17 May 01"

%A

%d

%B

%y

"%A, %d %B %y"

String from datetime

dt.strftime(format_string)

String from datetime

great_depression_crash = datetime.datetime(1929, 10, 29)
great_depression_crash

datetime.datetime(1929, 10, 29, 0, 0)

great_depression_crash.strftime("%a, %b %d, %Y")

'Tue, Oct 29, 1929'

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Intermediate Python for Finance