Time formats

Time formats#

  • Man’s inventivness regarding ways of representing dates and time points is truly inspiring … and a source of headache.

Oracle suggests:

  • time formats as (possible subsets of) HH:MM:SS XM (XM = AM/PM), with possible separators: “.”, “,”, “-”, “ “, “:”

  • 18 different date formats.

Unix timestamp

from datetime import datetime

# Getting the current date and time
dt = datetime.now()

# getting the timestamp
ts = datetime.timestamp(dt)

print("Date and time is:", dt)
print("Timestamp is:", ts)

Date and time is: 2024-12-04 21:23:08.050398
Timestamp is: 1733343788.050398

ISO standard#

W3.org: ISO 8601 and Wikipedia: ISO 8601

  • Year:

    • YYYY (e.g., 1997)

  • Year and month:

    • YYYY-MM (e.g., 1997-07)

  • Complete date:

    • YYYY-MM-DD (e.g., 1997-07-16)

  • Complete date plus hours and minutes:

    • YYYY-MM-DDThh:mmTZD (e.g., 1997-07-16T19:20+01:00)

  • Complete date plus hours, minutes and seconds:

    • YYYY-MM-DDThh:mm:ssTZD (e.g., 1997-07-16T19:20:30+01:00)

  • Complete date plus hours, minutes, seconds and a decimal fraction of a second

    • YYYY-MM-DDThh:mm:ss.sTZD (e.g., 1997-07-16T19:20:30.45+01:00)

where:

  • YYYY = four-digit year

  • MM = two-digit month (01=January, etc.)

  • DD = two-digit day of month (01 through 31)

  • hh = two digits of hour (00 through 23) (am/pm NOT allowed)

  • mm = two digits of minute (00 through 59)

  • ss = two digits of second (00 through 59)

  • s = one or more digits representing a decimal fraction of a second

  • TZD = time zone designator (Z or +hh:mm or -hh:mm)

Time conversion#

now = datetime.now()
formatted = now.strftime("%d/%m-%Y %H:%M:%S")
print("An arbitrary format:", formatted)

reformatted = datetime.strptime(formatted, "%d/%m-%Y %H:%M:%S")
print("Reformatted to the standard:", reformatted)

An arbitrary format: 04/12-2024 21:23:08
Reformatted to the standard: 2024-12-04 21:23:08

Exercise#

  • Read the white_rabbit.dat data using Pandas.

  • Convert the columns into standard Python format datetimes in the same timezone.

  • Concatenate the three columns into a single time series.

  • Convert it to your local timezone.

  • Confirm vilsually that you have handled each series correctly by plotting the resulting datetimes, achieving a perfectly straight line.

Resources#

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