Operators used in Python

Types of Operator

Python language supports the following types of operators.
Arithmetic Operators
Comparison (Relational) Operators
Assignment Operators
Logical Operators
Bitwise Operators
Membership Operators
Identity Operators

Python Arithmetic Operators:

Operator	Description
+ Addition	Adds values on either side of the operator.
- Subtraction	Subtracts right hand operand from left hand operand.
* Multiplication	Multiplies values on either side of the operator
/ Division	Divides left hand operand by right hand operand
% Modulus	Divides left hand operand by right hand operand and returns remainder
** Exponent	Performs exponential (power) calculation on operators
//	Floor Division - The division of operands where the result is the quotient in which the digits after the decimal point are removed.

Python Comparison Operators:

These operators compare the values on either sides of them and decide the relation among them. They are also called Relational operators.

Operator	Description
==	If the values of two operands are equal, then the condition becomes true.
!=	If values of two operands are not equal, then condition becomes true.
<>	If values of two operands are not equal, then condition becomes true.
>	If the value of left operand is greater than the value of right operand, then condition becomes true.
<	If the value of left operand is less than the value of right operand, then condition becomes true.
>=	If the value of left operand is greater than or equal to the value of right operand, then condition becomes true.
<=	If the value of left operand is less than or equal to the value of right operand, then condition becomes true.

Python Assignment Operators: 

Operator	Description
=	Assigns values from right side operands to left side operand
+= Add AND	It adds right operand to the left operand and assign the result to left operand
-= Subtract AND	It subtracts right operand from the left operand and assign the result to left operand
*= Multiply AND	It multiplies right operand with the left operand and assign the result to left operand
/= Divide AND	It divides left operand with the right operand and assign the result to left operand
%= Modulus AND	It takes modulus using two operands and assign the result to left operand
**= Exponent AND	Performs exponential (power) calculation on operators and assign value to the left operand
//= Floor Division	It performs floor division on operators and assign value to the left operand

Python Bitwise Operators:
Bitwise operator works on bits and performs bit by bit operation.

Operator	Description
& Binary AND	Operator copies a bit to the result if it exists in both operands
| Binary OR	It copies a bit if it exists in either operand.
^ Binary XOR	It copies the bit if it is set in one operand but not both.
~ Binary Ones Complement	It is unary and has the effect of 'flipping' bits.
<< Binary Left Shift	The left operands value is moved left by the number of bits specified by the right operand.
>> Binary Right Shift	The left operands value is moved right by the number of bits specified by the right operand.

Python Logical Operators: 
There are following logical operators supported by Python language.

Operator	Description
and Logical AND	If both the operands are true then condition becomes true.
or Logical OR	If any of the two operands are non-zero then condition becomes true.
not Logical NOT	Used to reverse the logical state of its operand.

Python Membership Operators:
Python’s membership operators test for membership in a sequence, such as strings, lists, or tuples.

Operator	Description
in	Evaluates to true if it finds a variable in the specified sequence and false otherwise.
not in	Evaluates to true if it does not finds a variable in the specified sequence and false otherwise.

Python Identity Operators:
Identity operators compare the memory locations of two objects. There are two Identity operators explained below:

Operator	Description
is	Evaluates to true if the variables on either side of the operator point to the same object and false otherwise.
is not	Evaluates to false if the variables on either side of the operator point to the same object and true otherwise.

Python Operators Precedence:
The following table lists all operators from highest precedence to lowest.

Operator	Description
**	Exponentiation (raise to the power)
~ + -	Ccomplement, unary plus and minus (method names for the last two are +@ and -@)
* / % //	Multiply, divide, modulo and floor division
+ -	Addition and subtraction
>> <<	Right and left bitwise shift
&	Bitwise 'AND'
^ |	Bitwise exclusive `OR' and regular `OR'
<= < > >=	Comparison operators
<> == !=	Equality operators
= %= /= //= -= += *= **=	Assignment operators
is is not	Identity operators
in not in	Membership operators
not or and	Logical operators

Data Types & Type Conversions in Python

Python has five standard data types 

• Numbers
• String
• List
• Tuple
• Dictionary

Python supports four different numerical types 

• int (signed integers)
• long (long integers, they can also be represented in octal and hexadecimal)
• float (floating point real values)
• complex (complex numbers)

Data Type Conversion

Sometimes, you may need to perform conversions between the built-in types. To convert between types, you simply use the type name as a function.

There are several built-in functions to perform conversion from one data type to another. These functions return a new object representing the converted value.

Function	Description
int(x [,base])	Converts x to an integer. base specifies the base if x is a string.
long(x [,base] )	Converts x to a long integer. base specifies the base if x is a string.
float(x)	Converts x to a floating-point number.
complex(real [,imag])	Creates a complex number.
str(x)	Converts object x to a string representation.
repr(x)	Converts object x to an expression string.
eval(str)	Evaluates a string and returns an object.
tuple(s)	Converts s to a tuple.
list(s)	Converts s to a list.
set(s)	Converts s to a set.
dict(d)	Creates a dictionary. d must be a sequence of (key,value) tuples.
frozenset(s)	Converts s to a frozen set.
chr(x)	Converts an integer to a character.
unichr(x)	Converts an integer to a Unicode character.
ord(x)	Converts a single character to its integer value.
hex(x)	Converts an integer to a hexadecimal string.
oct(x)	Converts an integer to an octal string.

Keywords/Reserved Words in Python

Below is the list of Python keywords/reserved words and you cannot use them as constant or variable or any other identifier names. 
All the Python keywords contain lowercase letters only.

And	exec	Not
Assert	finally	or
Break	for	pass
Class	from	print
Continue	global	raise
def	if	return
del	import	try
elif	in	while
else	is	with
except	lambda	yield

Python Installation and configuration

Installing Python on Windows:

First, download the latest version of Python 2.7 from the official Website. If you want to be sure you are installing a fully up-to-date version then use the “Windows Installer” link from the home page of the Python.org .

The Windows version is provided as an MSI package. To install it manually, just double-click the file. The MSI package format allows Windows administrators to automate installation with their standard tools.

By design, Python installs to a directory with the version number embedded, e.g. Python version 2.7 will install atC:\Python27\, so that you can have multiple versions of Python on the same system without conflicts. Of course, only one interpreter can be the default application for Python file types. It also does not automatically modify the PATHenvironment variable, so that you always have control over which copy of Python is run.

Typing the full path name for a Python interpreter each time quickly gets tedious, so add the directories for your default Python version to the PATH. Assuming that your Python installation is in C:\Python27\, add this to your PATH:

C:\Python27\;C:\Python27\Scripts\

You can do this easily by running the following in powershell:

[Environment]::SetEnvironmentVariable("Path", "$env:Path;C:\Python27\;C:\Python27\Scripts\", "User")

The second (Scripts) directory receives command files when certain packages are installed, so it is a very useful addition. You do not need to install or configure anything else to use Python. Having said that, I would strongly recommend that you install the tools and libraries described in the next section before you start building Python applications for real-world use. In particular, you should always install Setuptools, as it makes it much easier for you to use other third-party Python libraries.

Setuptools + Pip

The most crucial third-party Python software of all is Setuptools, which extends the packaging and installation facilities provided by the distutils in the standard library. Once you add Setuptools to your Python system you can download and install any compliant Python software product with a single command. It also enables you to add this network installation capability to your own Python software with very little work.
To obtain the latest version of Setuptools for Windows, run the Python script available here: ez_setup.py
You’ll now have a new command available to you: easy_install. It is considered by many to be deprecated, so we will install its replacement: pip. Pip allows for uninstallation of packages, and is actively maintained, unlike easy_install.
To install pip, run the Python script available here: get-pip.py

Source: http://docs.python-guide.org/en/latest/starting/install/win/

Once it is done we are ready to write programs in python but by using IDE it will be more easy to write programs..
So now we will configure python  with Eclipse IDE ..

Downloading Eclipse

You can download Eclipse here. The page should automatically detect your operating system. You want to download something called the "Eclipse SDK 3.2" (~120Mb).
Decompressing and opening should yield an Eclipse welcome screen. Amuse yourself with their tutorials and welcome messages as you wish. Then, Close the welcome screen to view the editor. You're now ready to install PyDev.

Installing PyDev

Eclipse installs extensions for you from within the application. All you need to provide is the web address of the extension you want to add (in our case, PyDev).

• From the menu system, select Help >> Software Updates >> Find and Install...
• Select Search for new features to install
• Click the "New Remote Site..." button and enter the following web address:
  http://pydev.sf.net/updates/
• Select the new site by checking its box, and click Finish
• Click to install PyDev and follow the directions, then wait for the new software to be downloaded and installed.
• Open the Preferences window within Eclipse and select Pydev >> Interpreter - Python"
• In the top of the preferences pane, click New... and locate your installation of Python (python.exe).

Creating a Python Project

Eclipse organizes all of your code into projects. You'll want to create a new Python project for all of your CS 188 code.

• Select File >> New >> Project...
• Select Pydev >> Pydev Project
• Give the project a name, and press Finished

Running Python from within Eclipse

Now you're ready to create a new python file and run it from within Eclipse. Right-click (control-click on Macs) on your project and create a new blank file. Make sure your file ends in .py, and Eclipse will recognize it as Python code.
Type in some Python code (for instance: print 2+2), then right-click on the Python file you've created and selectRun As >> Python run . You should see the output of your Python code in the console at the bottom of the Eclipse window.
Now that you've run the code once, you can press the green Run arrow at the top of the Eclipse window to run it again.

The PyDev perspective

Your installation of Pydev also changes the contextual menus and layout of the Eclipse GUI to better suit Python development. To enable these enhancements, select Window >> Open Perspective >> Other... and then select the Pydev perspective. The changes you'll find are subtle; for instance you can create a new Python module by right-clicking on your project (instead of a generic file).

Source: https://inst.eecs.berkeley.edu/~cs188/fa06/eclipse.html