Python Variables

Variable is a name of the memory location where data is stored. Once a variable is stored that means a space is allocated in memory.

Assigning values to Variable:

We need not to declare explicitly variable in Python. When we assign any value to the variable that variable is declared automatically.

The assignment is done using the equal (=) operator.

Eg:

Output:

>>> 
10
ravi
20000.67
>>>

Multiple Assignment:

Multiple assignment can be done in Python at a time.

There are two ways to assign values in Python:

1. Assigning single value to multiple variables:

Eg:

x=y=z=50
print x
print y
print z

Output:

>>> 
50
50
50
>>>

2.Assigning multiple values to multiple variables:

Eg:

a,b,c=5,10,15
print a
print b
print c

Output:

>>> 
5
10
15
>>>

The values will be assigned in the order in which variables appears.

Basic Fundamentals:

This section contains the basic fundamentals of Python like :

i)Tokens and their types.

ii) Comments

a)Tokens:

• Tokens can be defined as a punctuator mark, reserved words and each individual word in a statement.
• Token is the smallest unit inside the given program.

There are following tokens in Python:

• Keywords.
• Identifiers.
• Literals.
• Operators.

Tuples:

• Tuple is another form of collection where different type of data can be stored.
• It is similar to list where data is separated by commas. Only the difference is that list uses square bracket and tuple uses parenthesis.
• Tuples are enclosed in parenthesis and cannot be changed.

Eg:

>>> tuple=('rahul',100,60.4,'deepak')
>>> tuple1=('sanjay',10)
>>> tuple
('rahul', 100, 60.4, 'deepak')
>>> tuple[2:]
(60.4, 'deepak')
>>> tuple1[0]
'sanjay'
>>> tuple+tuple1
('rahul', 100, 60.4, 'deepak', 'sanjay', 10)
>>>

Dictionary:

• Dictionary is a collection which works on a key-value pair.
• It works like an associated array where no two keys can be same.
• Dictionaries are enclosed by curly braces ({}) and values can be retrieved by square bracket([]).

Eg:

>>> dictionary={'name':'charlie','id':100,'dept':'it'}
>>> dictionary
{'dept': 'it', 'name': 'charlie', 'id': 100}
>>> dictionary.keys()
['dept', 'name', 'id']
>>> dictionary.values()
['it', 'charlie', 100]
>>>