Basic fundamentals of Python part 1

There are following basic fundamentals of python as given below.

1. Tokens
2. Comments,Indentation and multi-lining
3. Python types
4. Operations and conversions
5. Built-in functions
6. Library functions

1.) Tokens :-

• Token can be defined as a reserved word, punctuation mark and each individual word in a statement .
• Token is the small unit in the given program.

There are some Tokens in python:-

1. Identifiers
2. keywords
3. Literals
4. Operators

1.) Identifiers :-

• Python identifier is a name used to identify a variable,Function,class,module, or other object.
• An  identifier is used to identify the literals used in the programs.

Rules for creating identifiers :-

1. Identifier name starts with alphabet (a-z, A-Z) or an underscore (_).
2. Identifier Name can not start with digits (0-9).
3. Keywords can not be used as Identifier.
4. identifier Name must not contain any white space, or special characters (@,#,$,^,&,*,%,!,/).
5. Identifier Name are case sensitive means Employee and employee is not the same.
6. Examples of valid identifiers: a_1, a55, _a, ab etc.
7. Examples of invalid Identifiers:
8. 2a, a 9, a/2, a%2 etc. 

Python Variables:-

• Variables is a name which is used to refer memory location.
• Variable is also used to hold value.
• In python , we need not to define DATA TYPE  (int,float, string,char etc.) before variable name.Python language is automatically detect the variable type when it runs,
• In python, variable name can be a group of letters and digits.But they are not  start with digits (1-9). 
• Python language is case sensitive,so variable name 'Ram' can not be same as variable name ram.

Declaring Variable and Assigning values :-

• Python language does not declare variable name before using in program.
• We don't need to declare variable explicitly in python.when we assign any value in any variable at that  time ,it is declared automatically.Means declaration and assignment of variable at a time.
• The eual (=) operator is used to assign value to a variable in python.

e.g.

(variable name = value)

a=5

b=10

name='Ram'

print (a )

print( b )

print (name)

Output :-

5

10

Ram

Python Data types :-

Python language is a dynamically typed language hence we need not to define the data type of the variable while declaring it.

• Python variable are built-in types.Means interpreter implicitly binds the value with its type.

Type () function :-

We can check the data type of the variable using  this type() function in python program.

Example:-

a=15

b=7.5

name='Ram'

print(type(a))

print (type(b))

print(type(name))

output:-

<class 'int'>

<class 'int'>

<class 'str'>

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