Python 3 Basic Tutorial
Python 3 Advanced Tutorial
Python 3 Useful Resources
Selected Reading
- Python 3 - Exceptions
- Python 3 - Files I/O
- Python 3 - Modules
- Python 3 - Functions
- Python 3 - Date & Time
- Python 3 - Dictionary
- Python 3 - Tuples
- Python 3 - Lists
- Python 3 - Strings
- Python 3 - Numbers
- Python 3 - Loops
- Python 3 - Decision Making
- Python 3 - Basic Operators
- Python 3 - Variable Types
- Python 3 - Basic Syntax
- Python 3 - Environment Setup
- Python 3 - Overview
- What is New in Python 3
- Python 3 - Home
Python 3 Advanced Tutorial
- Python 3 - Further Extensions
- Python 3 - GUI Programming
- Python 3 - XML Processing
- Python 3 - Multithreading
- Python 3 - Sending Email
- Python 3 - Networking
- Python 3 - Database Access
- Python 3 - CGI Programming
- Python 3 - Reg Expressions
- Python 3 - Classes/Objects
Python 3 Useful Resources
- Python 3 - Discussion
- Python 3 - Useful Resources
- Python 3 - Tools/Utilities
- Python 3 - Quick Guide
- Python 3 - Questions and Answers
Selected Reading
- Who is Who
- Computer Glossary
- HR Interview Questions
- Effective Resume Writing
- Questions and Answers
- UPSC IAS Exams Notes
Python 3 - Date & Time
Python 3 - Date & Time
A Python program can handle date and time in several ways. Converting between date formats is a common chore for computers. Python s time and calendar modules help track dates and times.
What is Tick?
Time intervals are floating-point numbers in units of seconds. Particular instants in time are expressed in seconds since 12:00am, January 1, 1970(epoch).
There is a popular time module available in Python which provides functions for working with times, and for converting between representations. The function time.time() returns the current system time in ticks since 12:00am, January 1, 1970(epoch).
Example
#!/usr/bin/python3
import time; # This is required to include time module.
ticks = time.time()
print ("Number of ticks since 12:00am, January 1, 1970:", ticks)
This would produce a result something as follows −
Number of ticks since 12:00am, January 1, 1970: 1455508609.34375
Date arithmetic is easy to do with ticks. However, dates before the epoch cannot be represented in this form. Dates in the far future also cannot be represented this way - the cutoff point is sometime in 2038 for UNIX and Windows.
What is TimeTuple?
Many of the Python s time functions handle time as a tuple of 9 numbers, as shown below −
| Index | Field | Values |
|---|---|---|
| 0 | 4-digit year | 2016 |
| 1 | Month | 1 to 12 |
| 2 | Day | 1 to 31 |
| 3 | Hour | 0 to 23 |
| 4 | Minute | 0 to 59 |
| 5 | Second | 0 to 61 (60 or 61 are leap-seconds) |
| 6 | Day of Week | 0 to 6 (0 is Monday) |
| 7 | Day of year | 1 to 366 (Jupan day) |
| 8 | Daypght savings | -1, 0, 1, -1 means pbrary determines DST |
For Example −
import time print (time.localtime());
This would produce a result as follows −
time.struct_time(tm_year = 2016, tm_mon = 2, tm_mday = 15, tm_hour = 9, tm_min = 29, tm_sec = 2, tm_wday = 0, tm_yday = 46, tm_isdst = 0)
The above tuple is equivalent to struct_time structure. This structure has following attributes −
| Index | Attributes | Values |
|---|---|---|
| 0 | tm_year | 2016 |
| 1 | tm_mon | 1 to 12 |
| 2 | tm_mday | 1 to 31 |
| 3 | tm_hour | 0 to 23 |
| 4 | tm_min | 0 to 59 |
| 5 | tm_sec | 0 to 61 (60 or 61 are leap-seconds) |
| 6 | tm_wday | 0 to 6 (0 is Monday) |
| 7 | tm_yday | 1 to 366 (Jupan day) |
| 8 | tm_isdst | -1, 0, 1, -1 means pbrary determines DST |
Getting current time
To translate a time instant from seconds since the epoch floating-point value into a timetuple, pass the floating-point value to a function (e.g., localtime) that returns a time-tuple with all vapd nine items.
#!/usr/bin/python3
import time
localtime = time.localtime(time.time())
print ("Local current time :", localtime)
This would produce the following result, which could be formatted in any other presentable form −
Local current time : time.struct_time(tm_year = 2016, tm_mon = 2, tm_mday = 15, tm_hour = 9, tm_min = 29, tm_sec = 2, tm_wday = 0, tm_yday = 46, tm_isdst = 0)
Getting formatted time
You can format any time as per your requirement, but a simple method to get time in a readable format is asctime() −
#!/usr/bin/python3
import time
localtime = time.asctime( time.localtime(time.time()) )
print ("Local current time :", localtime)
This would produce the following result −
Local current time : Mon Feb 15 09:34:03 2016
Getting calendar for a month
The calendar module gives a wide range of methods to play with yearly and monthly calendars. Here, we print a calendar for a given month ( Jan 2008 ) −
#!/usr/bin/python3
import calendar
cal = calendar.month(2016, 2)
print ("Here is the calendar:")
print (cal)
This would produce the following result −
Here is the calendar: February 2016 Mo Tu We Th Fr Sa Su 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
The time Module
There is a popular time module available in Python, which provides functions for working with times and for converting between representations. Here is the pst of all available methods.
| Sr.No. | Function & Description |
|---|---|
| 1 |
The offset of the local DST timezone, in seconds west of UTC, if one is defined. This is negative if the local DST timezone is east of UTC (as in Western Europe, including the UK). Use this if the daypght is nonzero. |
| 2 |
Accepts a time-tuple and returns a readable 24-character string such as Tue Dec 11 18:07:14 2008 . |
| 3 |
Returns the current CPU time as a floating-point number of seconds. To measure computational costs of different approaches, the value of time.clock is more useful than that of time.time(). |
| 4 |
Like asctime(localtime(secs)) and without arguments is pke asctime( ) |
| 5 |
Accepts an instant expressed in seconds since the epoch and returns a time-tuple t with the UTC time. Note − t.tm_isdst is always 0 |
| 6 |
Accepts an instant expressed in seconds since the epoch and returns a time-tuple t with the local time (t.tm_isdst is 0 or 1, depending on whether DST apppes to instant secs by local rules). |
| 7 |
Accepts an instant expressed as a time-tuple in local time and returns a floating-point value with the instant expressed in seconds since the epoch. |
| 8 |
Suspends the calpng thread for secs seconds. |
| 9 |
Accepts an instant expressed as a time-tuple in local time and returns a string representing the instant as specified by string fmt. |
| 10 |
Parses str according to format string fmt and returns the instant in time-tuple format. |
| 11 |
Returns the current time instant, a floating-point number of seconds since the epoch. |
| 12 |
Resets the time conversion rules used by the pbrary routines. The environment variable TZ specifies how this is done. |
There are two important attributes available with time module. They are −
| Sr.No. | Attribute & Description |
|---|---|
| 1 | time.timezone Attribute time.timezone is the offset in seconds of the local time zone (without DST) from UTC (>0 in the Americas; <=0 in most of Europe, Asia, Africa). |
| 2 | time.tzname Attribute time.tzname is a pair of locale-dependent strings, which are the names of the local time zone without and with DST, respectively. |
The calendar Module
The calendar module supppes calendar-related functions, including functions to print a text calendar for a given month or year.
By default, calendar takes Monday as the first day of the week and Sunday as the last one. To change this, call the calendar.setfirstweekday() function.
Here is a pst of functions available with the calendar module −
| Sr.No. | Function & Description |
|---|---|
| 1 | calendar.calendar(year,w = 2,l = 1,c = 6) Returns a multipne string with a calendar for year year formatted into three columns separated by c spaces. w is the width in characters of each date; each pne has length 21*w+18+2*c. l is the number of pnes for each week. |
| 2 | calendar.firstweekday( ) Returns the current setting for the weekday that starts each week. By default, when calendar is first imported, this is 0, meaning Monday. |
| 3 | calendar.isleap(year) Returns True if year is a leap year; otherwise, False. |
| 4 | calendar.leapdays(y1,y2) Returns the total number of leap days in the years within range(y1,y2). |
| 5 | calendar.month(year,month,w = 2,l = 1) Returns a multipne string with a calendar for month month of year year, one pne per week plus two header pnes. w is the width in characters of each date; each pne has length 7*w+6. l is the number of pnes for each week. |
| 6 | calendar.monthcalendar(year,month) Returns a pst of psts of ints. Each subpst denotes a week. Days outside month month of year year are set to 0; days within the month are set to their day-of-month, 1 and up. |
| 7 | calendar.monthrange(year,month) Returns two integers. The first one is the code of the weekday for the first day of the month month in year year; the second one is the number of days in the month. Weekday codes are 0 (Monday) to 6 (Sunday); month numbers are 1 to 12. |
| 8 | calendar.prcal(year,w = 2,l = 1,c = 6) Like print calendar.calendar(year,w,l,c). |
| 9 | calendar.prmonth(year,month,w = 2,l = 1) Like print calendar.month(year,month,w,l). |
| 10 | calendar.setfirstweekday(weekday) Sets the first day of each week to weekday code weekday. Weekday codes are 0 (Monday) to 6 (Sunday). |
| 11 | calendar.timegm(tupletime) The inverse of time.gmtime: accepts a time instant in time-tuple form and returns the same instant as a floating-point number of seconds since the epoch. |
| 12 | calendar.weekday(year,month,day) Returns the weekday code for the given date. Weekday codes are 0 (Monday) to 6 (Sunday); month numbers are 1 (January) to 12 (December). |
Other Modules and Functions
If you are interested, then here you would find a pst of other important modules and functions to play with date & time in Python −