Time handling

Gets the current local date and time for timestamping or time calculations.

Web development: logging the time of a user request for audit trails; Data analysis: recording the start time of a process to measure performance; Automation: scheduling a task to run at a specific time by comparing with current time

Python applications involving time-sensitive operations, such as web backends, data pipelines, or system automation scripts.

datetime.now()

datetime.now()

• time module for timezone handling
• timedelta for duration calculations

• datetime.utcnow() for UTC time (now deprecated in favor of timezone-aware datetimes)
• datetime.now(timezone.utc) for explicit UTC

Using datetime.now() without importing datetime (NameError: name 'datetime' is not defined); Confusing datetime.now() with time.time() which returns a float timestamp; Forgetting that datetime.now() returns a naive datetime object without timezone info

time.time(): returns seconds since epoch as a float; datetime.today(): similar to now() but may not be available in all contexts

Coming from JavaScript: may use Date.now() which returns milliseconds — Python's datetime.now() returns a datetime object; Coming from Bash: may use date command which outputs formatted string — Python requires explicit formatting

• datetime.time
• datetime.date
• timedelta

Avoid using naive datetimes in timezone-sensitive applications; Performance impact is negligible as it's a simple system call; Be aware that on some systems, the clock may be adjusted backward (e.g., NTP sync)

Enables accurate time-based logging and scheduling; Prevents errors from using system time incorrectly in distributed systems

Like checking a wall clock: datetime.now() gives you the current time without any setup, just glance and read.

Learn timezone-aware datetimes with datetime.now(timezone.utc)