Time concept
UTC and time zone
UTC is the abbreviation of Coordinated Universal Time and is the global standard of time. UTC time is not affected by time zones and daylight saving time, and is the standard of time. Times around the world are adjusted based on UTC time as a reference.
The time zone is Time Zone, which is a region on the earth divided by longitude. Each region has its own standard time. The gap between time zone and UTC time is usually in hours (but some time zones are offset by 30 minutes). The entire earth is divided into 24 main time zones, each covering approximately 15 degrees of longitude (360 degrees/24 hours)
Beijing time is East Eighth District, which is 8 hours off from UTC time, which is UTC+8. In the world, there are also Australia's regions in East Eighth District.
New York time is the West Five District, which is UTC-5, so the standard time difference from the East Eight District in Beijing time is 13 hours. But it should be noted that when the New York area starts daylight saving time, it will become UTC-4, which is a common 12-hour time difference.
Tokyo time is East Nine District, which is UTC+9. Therefore, the difference between East Eight District in Beijing time is 1 hour, and 1 hour early.
Daylight saving time
Daylight saving time is a system of artificial clock adjustments. It usually adjusts the clock forward for an hour in spring. Its purpose is to extend the sunshine time in the evening, aiming to make more efficient use of daylight resources and reduce energy consumption.
Among them, high-latitude countries in the northern hemisphere usually use daylight saving time because of their high latitude and great changes in sunshine. In contrast, sunshine changes in areas close to the equator, so daylight saving time is usually not used. For example, most Asian countries, such as China, Japan, and South Korea, do not use daylight saving time.
People who have not used the Summer Time area usually don’t know much about the role of Summer Time. Specifically: During Summer Time, the clock is turned up for an hour. This means that people actually wake up one hour earlier than usual according to the new schedule, but because it is early in summer, it has little impact on life. When you get off work in the afternoon, the sky is still bright at the new time and people can enjoy more sunshine after get off work.
Timestamp
Timestamp is a digital format that represents a specific time point. It is represented by the number of seconds or milliseconds elapsed since 00:00:00 on January 1, 1970. The time stamp can accurately identify a specific time point, which is not affected by the time zone.
Time stamps play a big role in programming, such as recording a system event, the time of user registration, or calculating the time interval by calculating the difference in timestamps.
time
General formatting
time mainly deals with time acquisition and simple formatting. If more complex date and time operations are required, you should try using datetime.
Commonly used formatting strings are shown below, and the same is true in datetime
- %Y: Four-digit year
- %m: Two months (01-12)
- %d: two digit date (01-31)
- %H: Two digits of hours (00-23)
- %M: Two digit minutes (00-59)
- %S: Two digits of seconds (00-59)
Timestamp
Get the current timestamp
import time
timestamp = ()
print("Current timestamp:", timestamp)
Time stamps can be used to record time intervals, but if you want to make more accurate timing, you can use it.
import time
start = time.perf_counter()
(2)
end = time.perf_counter()
print(f"Time-consuming operation： {end - start} Second")
Time stamp to time object
Convert timestamp to struct_time local time
timestamp = ()
local_time = (timestamp)
print("Local time:", local_time)
Convert timestamp to utc time
timestamp = ()
utc_time = (timestamp)
print("UTC Time:", utc_time)
Time object to time stamp
import time
struct = ("2024-11-02 22:00:00", "%Y-%m-%d %H:%M:%S")
timestamp = (struct)
print("Timestamp:", timestamp) # Timestamp: 1730556000.0Time formatting
Quickly convert a timestamp to readable time
timestamp = () readable_time = (timestamp) print(readable_time) # Format such as Sat Nov 2 10:32:27 2024
Create a time object based on a time string
time_str = "2024-11-02 22:00:00" parsed_time = (time_str, "%Y-%m-%d %H:%M:%S") print(parsed_time)
Convert to string according to time object
time_str = "2024-11-02 22:00:00"
parsed_time = (time_str, "%Y-%m-%d %H:%M:%S")
formatted_time = ("%Y year %m month %d day %H point %M point", parsed_time)
print("Format time:", formatted_time) # Format time: 22:00 on November 2, 2024Time pause
Time will not be paused, but in fact this function is paused by the program.
import time
print("Before pause")
(3) # Pause for 3 secondsprint("After pause")
datetime
date date
Get the current date
today = ()
print("Today's date:", today) # Format as 2024-11-02datetime datetime
Get the current time
now_time = ().time()
print("Current time:", now_time) # Format as 10:46:50.506231Get the current date and time
now = ()
print("Current date and time:", now) # Format as 2024-11-02 10:47:44.299445Get UTC time
utc_now = ()
print("UTC Time:", utc_now)
Create a datetime object
Create a date object
specific_date = (2024, 11, 2)
print("Specific date:", specific_date)
Create a time object
specific_time = (22, 0, 0)
print("Specific time:", specific_time)
Create a datetime object
specific_datetime = (2024, 11, 2, 22, 0, 0)
print("Specific date and time:", specific_datetime)
Time string formatting and parsing
Time string formatting
now = ()
formatted = ("%Y-%m-%d %H:%M:%S")
print("Format date time:", formatted)
Time string parsing
time_str = "2024-11-2 22:00:00"
parsed_datetime = (time_str, "%Y-%m-%d %H:%M:%S")
print("Resolved Date and Time Object:", parsed_datetime)
Time interval
Calculate the date of the time interval using timedelta
from datetime import date, timedelta
today = ()
future_date = today + timedelta(days=10)
print("Date after 10 days:", future_date)
past_date = today - timedelta(weeks=1)
print("Date one week ago:", past_date)
Calculate the date and time of the time interval
from datetime import datetime, timedelta
now = ()
future_time = now + timedelta(minutes=10)
print("Date time after 10 minutes:", future_time)
past_time = now - timedelta(hours=2)
print("Date time 2 hours ago:", past_time)
zoneinfo
Time conversion
After python 3.9, zoneinfo was introduced to handle time zones and can be directly used for datetime
from datetime import datetime
from zoneinfo import ZoneInfo
now_utc = (ZoneInfo("UTC"))
print("UTC Time:", now_utc)
# Convert to Beijing timenow_beijing = now_utc.astimezone(ZoneInfo("Asia/Shanghai"))
print("Beijing time:", now_beijing)
# Convert to New York timenow_newyork = now_utc.astimezone(ZoneInfo("America/New_York"))
print("New York Time:", now_newyork)
In fact, time conversion can also be calculated by yourself. For example, we have learned that Beijing time is UTC+8 and New York time is UTC-5.
from datetime import datetime, timedelta
now_utc = ()
print("UTC Time:", now_utc)
now_beijing = now_utc + timedelta(hours=8)
print("Beijing time:", now_beijing)
now_newyork = now_utc - timedelta(hours=5)
print("New York Time:", now_newyork)
List all time zones
All time zones
import zoneinfo print(zoneinfo.available_timezones())
Traversal to find the Asia time zone
import zoneinfo
for zone in zoneinfo.available_timezones():
if "Asia" in zone:
print(zone)
Get time zone time
If you always set the local time zone time by yourself when using the current time, without relying on machine settings, you can get better cross-platformity
from datetime import datetime
from zoneinfo import ZoneInfo
tz_shanghai = ZoneInfo("Asia/Shanghai")
tz_newyork = ZoneInfo("America/New_York")
now_shanghai = (tz_shanghai)
now_newyork = (tz_newyork)
print("Beijing time:", now_shanghai)
print("New York Time:", now_newyork)The above is a detailed explanation of how to correctly use timestamps, dates, time and time zones in Python. For more information about Python time, please follow my other related articles!