Python has become one of the most popular dynamic,programming languages, along with Perl, Ruby, and others. Python and Ruby havebecome especially popular in recent years for building websites using their numerous web frameworks, like Rails (Ruby) and Django (Python). Such languages are often called scripting languages as they can be used to write quick-and-dirty small programs,or scripts. I don’t like the term “scripting language” as it carries a connotation that they cannot be used for building mission-critical software. Among interpreted languages Python is distinguished by its large and active scientific computing community. Adoption of Python for scientific computing in both industry applications and academic research has increased significantly since the early 2000s.
For data analysis and interactive, exploratory computing and data visualization,Python will inevitably draw comparisons with the many other domain-specific open source and commercial programming languages and tools in wide use, such as R, MATLAB,SAS, Stata, and others. In recent years, Python’s improved library support (primarily pandas) has made it a strong alternative for data manipulation tasks. Combined with Python’s strength in general purpose programming, it is an excellent choice as a single language for building data-centric applications.

Concatenation

>>>’Zend’ + ‘Anwar’

Zendanwar

>>>’Zend’ *3

ZendZendZend

Iterating Through String

>> count = 0
>>> for str in ‘Zend Anwar’:
if(str == ‘n’):
count += 1

>>> print(count, “String Found”)
2 String Found

def functionname(parameters):
“””docstring”””
statement(s)
return [expression]

Example:
#!/usr/bin/python

# Function definition is here
def ima( lovestr ):
“This prints a passed string into this function”
print lovestr
return;

# Now you can call ima function
ima(“I’m fall in love!”)

>>> star =  input(“Enter the star to draw: “)
Enter the star to draw: *
>>> limit = int(input(“Enter the limit: “))
Enter the limit: 10
>>> for i in range(1, limit+1):
print (star*i)

Output–   
*
**
***
****
*****
******
*******
********
*********
**********

>>> for var in “zend-anwar”:
if var == “-“:
continue
print (var)

output–
z
e
n
d
a
n
w
a
r

>>> for var in “zend-anwar”:
if var == “-“:
break
print (var)

output—   
z
e
n
d

The Internet Protocol assigns a 4-byte address to every computer connected to the network. Such
addresses are usually written as four decimal numbers, separated by periods, which each represent a
single byte of the address. Each number can therefore range from 0 to 255. So an IP address looks like
this:
202.168.3.180

Because purely numeric addresses can be difficult for humans to remember, the actual people using
the Internet are generally shown hostnames rather than IP addresses. The user can simply type
google.com and forget that behind the scene this resolves to an address like 74.125.67.103, to which
their computer can actually address packets for transmission over the Internet.

#!/usr/bin/python
import socket
hostname = ‘maps.google.com’
IPaddress = socket.gethostbyname(hostname)
print ‘The address of’, hostname, ‘is’, IPaddress

• def can contain multiple expressions whereas lamda is a single expression function
• def creates a function and assigns a name so as to call it later. lambda creates a function and returns the function itself
• def can have return statement. lambda cannot have return statements
• lambda can be used inside list, dictionary.

>>> sqr = []
>>> for i in range(10):
sqr.append(i**2)

>>> sqr
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

Combination 

comb = []

>>> for i in [1, 5, 3]:
for j in [2,1,5]:
if i!=j:
comb.append((i,j))

>>> comb
[(1, 2), (1, 5), (5, 2), (5, 1), (3, 2), (3, 1), (3, 5)]

>>> stack = [11,22,33,44,55,66,77]
>>> stack.append(88)
>>> stack
[11, 22, 33, 44, 55, 66, 77, 88]
>>> stack.append(99)
>>> stack
[11, 22, 33, 44, 55, 66, 77, 88, 99]
>>> stack.pop()
99
>>> stack.pop()
88
>>> stack.pop()
77
>>> stack.pop()
66
>>> stack
[11, 22, 33, 44, 55]