The calendar Module of Python

The calendar module supplies 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 calendar.setfirstweekday() functionThe calendar module supplies 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 calendar.setfirstweekday() function

SN	Function with Description
1	calendar.calendar(year,w=2,l=1,c=6) Returns a multiline string with a calendar for year formatted into three columns sparated by c spaces. W is the width in characters of each date; each line has length 21*w+18+2*c. | is the number of lines 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 multiline string with a calendar for month of year, one line per week plus two header lines. w is the width in characters of each date; each line has length 7*w+6
6	calendar.monthcalendar(year,month) Returns a list of lists of ints. Each sublist 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 th 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.timegm(tupletime) 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).

The time Module of Python

There is a popular time module available in Python which provides functions for working with times, and for converting between representations. Here is the list of all available methods:

SN	Function with Description
1	time.altzone 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). Only use this if daylight is nonzero.
2	time.asctime([tupletime]) Accepts a time-tuple and returns a readable 24-character string such as ‘Tue Dec 11 18:07:14 2008’.
3	time.clock() 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	time.ctime[secs] Like asctime (localtime(secs)) and without arguments is like asctime()
5	time.gmtime([secs]) 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	time.localtime([secs]) 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 applies to instant secs by local rules).
7	time.mktime(tupletime) 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	time.sleep(secs) Suspends the calling thread for secs seconds.
9	time.strftime(fmt[,tupletime]) Accepts an instant expressed as a time-tuple in local time and returns a string representing the instant as specified by string fmt.
10	time.strptime(str,fmt= ‘%a %b %d %H;%M;%S%Y’) Parses str according to format string fmt and returns the instant in time-tuple format.
11	time.time() Returns the current time instant, a floating-point number of seconds since the epoch.
12	time.tzset() Resets the time conversion rules used by the library routines. The environment variable TZ specifies how this is done
13	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).
14	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.

Getting calendar for a month -:

Example:

The calendar module gives a wide range of methods to play with yearly and monthly  calendar.

Here we print a calendar for a given month (Jan 2008):

#!/usr/bin/python

Import calendar

cal = calendar.month(2008, 1)

print “Here is the calendar:”

print cal;

This will produce following result:

Here is the calendar:

            January 2008

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  30  31

Getting formatted time -:

Example:

You can format any time as per your requirement, but simple method to get time in readable format is asctime() :

#!/usr/bin/python

Import time;

localtime = time.asctime ( time.localtime(time.time())

print “Local current time  :”, localtime

This would produce following result:

Local current time: Tue Jan 13  10:17:09 2009

Getting current Time -:

Example:

To translate a time instant from a seconds since the epoch floating-point value into a time-tuple, pass the floating-point value to a function (e.g. localtime) that returns a time-tuple with all nine items valid:

#!/usr/bin/python

localtime = time.localtime(time.time())

print “Local current time :”, localtime

This will produce following result which could be formatted in any other presentable form:

Local current time  :  (2008, 5, 15, 12, 55, 32, 0, 136, 1)

What is TimeTuple

Index	Field	Values
0	4-digit year	2008
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 (Julian day)
8	Daylight savings	-1, 0, 1, -1 means library determines DST

The above tuple is equivalent to struct_time structure. This structure has following attributes:

Index	Attributes	Values
0	tm_year	2008
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(Julian day)
8	Tm_isdst	-1, 0, 1, -1 means library determines DST

Time and date

A Python program can handle date & 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

Example:

#!/usr/bin/python

Import  time;  #This is required  to include time module.

ticks = time.time()

print  “Number of ticks since 12:00 am, January 1, 1970 :”, ticks

This would produce a result something as follows :

Number of ticks since 12:00 am, January 1, 1970: 7186862.73399

For loop of Python

The for loop in python has the ability to iterate over the items of any sequence, such as a list or a string.

The syntax of the loop look is:

for iterating_var in sequence:

            statements(s)

if a sequence contains an expression list, it is evaluated first. Then, the first item in the sequence is assigned to the iterating variable iterating_var. Next, the statements block is executed. Each item in the list is assigned to iterating_var, and the statements(s) block is executed until the entire sequence is exhausted.

Note: in python, all the statements indented by the same number of character spaces after a programming construct are considered to be part of a single block of code. Python uses indentation as its method of grouping statements.

Example:

#!/usr/bin/python

for letter in ‘python’ :            #First Example

            print ‘Curre t Letter : ’, letter

fruits = [‘banana’, ‘apple’, ‘mango’]

for fruit in fruits:        #Second Example

            print  ‘Current fruit :’, fruit

print  “Good bye!”

This will produce following result:

Current Letter  :  P

Current Letter  :  y

Current Letter  :  t

Current Letter  :  h

Current Letter  :  o

Current Letter  :  n

Current fruit    : banana

Current fruit   : apple

Current fruit  :  mango

Good bye!

Iterating by sequence index:

An alternative way of iterating through each item is by index offset into the sequence itself:

Example:

#!/usr/bin/python

fruits = [‘banana’, ‘apple’, ‘mango’]

for index in range (len(fruits)):

              print  ‘Current fruit  :’,  fruits[index]

print “Good bye!”

This will produce following result:

Current fruit  : banana

Current fruit  : apple

Current fruit  : mango

Good bye!

Single Statement Suites

Similar to the if statement syntax, if your while clause consists only of a single statement, it may be placed on the same line as the while header.

Here is the syntax of a one – line while clause:

While expression : statement

The Infinite Loops

You must use caution when using while loops because of the possibility that this condition never resolves to a false value. This results in a loop that never ends. Such a loop is called an infinite loop.

An infinite loop might be useful in client/server programming where the server needs to run continuously so  that client programs can communicate with it as and when required.

Example:

Following loop will continue till you enter CTRL + C

#!/usr/bin/python

var = 1

while var == 1 :  #This construct an infinite loop

     num = raw_input (“Enter a number  :”)

    print “You entered: ”, num

print “Good bye!”

This will produce following result:

Enter a number  :20

You entered: 20

Enter a number  :29

You entered: 29

Enter a number  :3

You entered: 3

Enter a number between : Trackback  (most recent call last):

   File “text.py”, line 5, in <module>

    num = raw_input(“Enter a number : ”)

keyboardInterrupt

while Loop of python

The while loop is one of the looping constructs available in Python. The while loop continues until the expression becomes false. The expression has to be a logical expression and must return either a true or a false value.

The syntax of the while loop is :

While expression:

     Statement(s)

Here expression statement is evaluated first. If expression is true that is, then the statement(s) block is executed repeatedly until expression becomes false. Otherwise, the next statement following the statement(s) block is executed.

Example:

#!/usr/bin/python

count = 0

while (count < 9)

            print ‘The count is :’ , count

            count = count + 1

print “Good bye!”

This will produce following result:

The count is : 0

The count is : 1

The count is : 2

The count is : 3

The count is : 4

The count is : 5

The count is : 6

The count is : 7

The count is : 8

Good bye!