Convert datetime to Unix timestamp and convert it back in python

Handling timezones in conversion

When dealing with different timezones, it's essential to use timezone-aware datetime objects to avoid any potential mismatches or errors:

from datetime import datetime, timezone

# Datetime with UTC timezone
dt_utc_aware = datetime.now(timezone.utc)

# Conversion to Unix timestamp
unix_timestamp = dt_utc_aware.timestamp()

# Conversion back to datetime
aware_unix_to_dt = datetime.fromtimestamp(unix_timestamp, timezone.utc)
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Now every time your timestamp travels abroad, it can tell exactly what time it is back home!

Counting seconds since epoch

If you're nostalgic about the good old days of 1970, you can use total_seconds() and calculate the number of seconds since the epoch:

from datetime import datetime, timedelta

# timedelta since the epoch
td_since_epoch = datetime.now() - datetime(1970, 1, 1)

# Total seconds since epoch
total_seconds = td_since_epoch.total_seconds()

# Datetime from total seconds
datetime_from_seconds = datetime(1970, 1, 1) + timedelta(seconds=total_seconds)
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We're talking about ~1.6 trillion seconds since the epoch. Yeah, time flies!

On daylight saving time

When handling local times and Unix timestamps, potential shifts due to daylight saving time (DST) changes need to be considered:

import time
from datetime import datetime, timezone

local_dt = datetime(2023, 3, 8, 12, 0)  # A date before DST change
unix_timestamp_before_dst = time.mktime(local_dt.timetuple())
reverted_dt_before_dst = datetime.fromtimestamp(unix_timestamp_before_dst, timezone.utc)

local_dt_after_dst = datetime(2023, 3, 9, 12, 0)  # A date after DST change
unix_timestamp_after_dst = time.mktime(local_dt_after_dst.timetuple())
reverted_dt_after_dst = datetime.fromtimestamp(unix_timestamp_after_dst, timezone.utc)
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That's right, even your code needs to remember to spring forward and fall back on DST shifts!

Attention to platform specifics

Remember, not all platforms are created equal. For instance, using strftime('%s') to obtain the seconds since epoch may not yield correct results on some of them:

from datetime import datetime

# The way below may not be consistent across platforms
# seconds_since_epoch_str = datetime.now().strftime('%s')

# Instead, use this for a safer ride
seconds_since_epoch = datetime.now().timestamp()
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So, make sure you check the compatibility of your platform with this magic '%s' spell before casting it!