Dates in Python — datetime, strftime, timedelta

The datetime Module

Python's built-in datetime module provides classes for working with dates and times. The main classes are date, time, datetime, and timedelta.

Getting Current Date & Time

Current Date & Time

from datetime import date, time, datetime

# Current date
today = date.today()
print(today)           # 2024-01-15
print(today.year)      # 2024
print(today.month)     # 1
print(today.day)       # 15

# Current date and time
now = datetime.now()
print(now)             # 2024-01-15 14:30:45.123456
print(now.hour)        # 14
print(now.minute)      # 30
print(now.second)      # 45

# UTC time
from datetime import timezone
utc_now = datetime.now(timezone.utc)
print(utc_now)

Creating Date & Time Objects

Creating Objects

from datetime import date, time, datetime

# Specific date
birthday = date(1990, 6, 15)
print(birthday)         # 1990-06-15

# Specific time
alarm = time(7, 30, 0)
print(alarm)            # 07:30:00

# Specific datetime
event = datetime(2024, 12, 25, 18, 0, 0)
print(event)            # 2024-12-25 18:00:00

# From timestamp (Unix time)
import time as t
ts = datetime.fromtimestamp(t.time())
print(ts)

# From ISO format string
dt = datetime.fromisoformat("2024-06-15T14:30:00")
print(dt)

Formatting Dates (strftime)

Use strftime() to format a datetime as a string.

strftime - Format Codes

from datetime import datetime

now = datetime(2024, 6, 15, 14, 30, 45)

print(now.strftime("%Y-%m-%d"))           # 2024-06-15
print(now.strftime("%d/%m/%Y"))           # 15/06/2024
print(now.strftime("%B %d, %Y"))          # June 15, 2024
print(now.strftime("%A, %B %d, %Y"))      # Saturday, June 15, 2024
print(now.strftime("%I:%M %p"))           # 02:30 PM
print(now.strftime("%H:%M:%S"))           # 14:30:45
print(now.strftime("%Y-%m-%dT%H:%M:%S"))  # ISO 8601

# Common format codes:
# %Y = 4-digit year    %m = month (01-12)   %d = day (01-31)
# %H = hour (00-23)    %M = minute (00-59)  %S = second (00-59)
# %I = hour (01-12)    %p = AM/PM           %A = weekday name
# %B = month name      %j = day of year     %W = week number

Parsing Dates (strptime)

strptime - Parse Strings

from datetime import datetime

# Parse a date string into a datetime object
dt = datetime.strptime("2024-06-15", "%Y-%m-%d")
print(dt)           # 2024-06-15 00:00:00

dt2 = datetime.strptime("June 15, 2024 2:30 PM", "%B %d, %Y %I:%M %p")
print(dt2)          # 2024-06-15 14:30:00

# Convert between formats
user_input = "15/06/2024"
parsed = datetime.strptime(user_input, "%d/%m/%Y")
formatted = parsed.strftime("%B %d, %Y")
print(formatted)    # June 15, 2024

Date Arithmetic with timedelta

timedelta

from datetime import date, datetime, timedelta

today = date.today()

# Add/subtract days
tomorrow = today + timedelta(days=1)
last_week = today - timedelta(weeks=1)
next_month = today + timedelta(days=30)

print(tomorrow)     # tomorrow's date
print(last_week)    # 7 days ago
print(next_month)   # 30 days from now

# Difference between two dates
start = date(2024, 1, 1)
end = date(2024, 12, 31)
diff = end - start
print(diff.days)    # 365

# Age calculator
birthday = date(1990, 6, 15)
today = date.today()
age = today.year - birthday.year
if (today.month, today.day) < (birthday.month, birthday.day):
    age -= 1
print(f"Age: {age}")

# Time difference
start_time = datetime(2024, 1, 1, 9, 0, 0)
end_time = datetime(2024, 1, 1, 17, 30, 0)
duration = end_time - start_time
print(duration)              # 8:30:00
print(duration.seconds)      # 30600 seconds
print(duration.seconds // 3600)  # 8 hours