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!