In interactive mode Python code can be directly typed and the interpreter displays the result (s) immediately. The interactive mode can also be used as a simple calculator.

Python shell can be used in two ways, viz. Interactive mode and Script mode.

The version 3. x of Python IDLE (Integrated Development Learning Environment) is used to develop and run Python code.

The different operators that can be used in python are
(i) Arithmetic operators
(ii) Relational or Comparative operator
(iii) Logical operators
(iv) Assignment operators
(v) Conditional operator

(i) In Python, programs can be written in two namely Interactive mode and script mode.
(ii) Interactive mode allows us to write codes in Python command prompt (>>>).
(iii) Script mode is used to create and edit python source file.

(i) In Python, programs can be written in two ways namely Interactive mode and Script mode.
(ii) The Interactive mode allows us to write codes in Python command prompt >>> whereas in script mode programs can be written and stored as separate file with the extension.
(iii) py and executed. Script mode is used to create and edit python source file.

(i) It is a general purpose programming language which can be, used for both scientific and non-scientific programming.
(ii) It is a platform independent programming language.
(iii) The programs written in Python are easily readable and understandable.

(i) In Python, a string literal is a sequence 0 characters surrounded by quotes. Python supports Single, double and triple quotes for a string.
(ii) A character literal is a single character surrounded by single or double quotes. The value with triple-quote u ''' ''' is used to give multi-line string literal.
Program:
To test String Literals:
# Demo Program to test String Literals
strings = "This is Python"
char = "C"
multiline_str = ''''This is a multiline string with more than one line code.'''
print (strings)
print (char)
print (multiline_str)
# End of the Program
Output:
This is Python
C
This is a multiline string with more than one line code.

(i) Ternary operator is also known as conditional operator that evaluate something based on a condition being true or false.
(ii) It simply allows testing a condition in a single line replacing the multiline if-else making the code compact. The syntax for conditional operator is,
Variable Name = [on_true] if [Test expression]
else [on_false]
(iii) Example:
min = 50 if 49 < 50 else 70 # min = 50
min = 50 if 49 > 50 else 70 # min = 70

(i) An arithmetic operator is a mathematical operator that takes two operands and performs a calculation on them. They are used for simple arithmetic.
(ii) Most computer languages contain a set of such operators that can be used within equations to perform different types of sequential calculations.
(iii) Python supports the following Arithmetic operators.

Type a Value for X : 10
The x + = 20 is = 30
The x - = 5 is = 25
The x * = 5 is = 125
The x / = 2 is = 62.5
The x % = 3 is = 2.5
The x ** = 2 is = 6.25
The x// = 3 is = 2.0

Python breaks each logical line into a sequence of elementary lexical components known as Tokens. The normal token types are
(i) Identifiers,
(ii) Keywords,
(iii) Operators,
(iv) Delimiters and
(v) Literals.
(i) Identifiers:
1. An Identifier is a name used to identify a variable, function, class, module or object.
2. An identifier must start with an alphabet (A..Z or a..z) or underscore (-).
3. Identifiers may contain digits (0 .. 9).
4. Python identifiers are case sensitive i.e. uppercase and lowercase letters are distinct.
5. Identifiers must not be a python keyword.
6. Python does not allow punctuation character such as %,$, @ etc., within identifiers.
Example of valid identifiers.
Sum, total_marks, regno, num1.
Example of invalid identifiers
12 Name, name $, total-mark, continue.
Keywords:
Keywords are special words used by Python interpreter to recognize the structure of program. As these words have specific meaning for interpreter, they cannot be used for any other purpose.

Operators:
In computer programming languages operators are special symbols which represent computations, conditional matching etc. The value of an operator used is called operands. Operators are categorized as Arithmetic, Relational, Logical, Assignment etc. Value and variables when used with operator are known as operands.
i) Arithmetic operators
An arithmetic operator is a mathematical operator that takes two operands and performs a calculation on them. They are used for simple arithmetic. Most computer languages contain a set of such operators that can be used within equations to perform different types of sequential calculations.
Python supports the following Arithmetic operators.

ii) Relational or Comparative Operators
A Relational operator is also called as comparative operator which checks the relationship between two operands. If the relation is true, it returns True; otherwise it returns False.
Python supports following relational operators.

ii) Logical Operators
In Python, Logical operators are used to perform logical operations on the given relational expressions. There are three logical operators they are and, or and not.

iv) Assignment Operators
In Python, =is a simple assignment operator to assign values to variables Let a=5 and b=10 assigns the value.5 to a and 10 to b these two assignment statement can also be given as a,b=5,10 that assigns the value 5 and 10 on the right to the variables a and b respectively.
There are various compound operators in python Like +=,-=,*=,/=,%=,**= and // = are also available.

v) Conditional Operator
Ternary operator is also known as Conditional operator that evaluate something based on a condition being true or false. It simply allows testing a condition in a single line replacing the multiline if-else making the code compact. The syntax conditional operator is
Variable Name = [on_true] if [Test expression] else [on_false]
Example:
min = 50 if 49<50 else 70 # min = 50
min = 50 if 49>50 else 70 # min = 70
Delimiters:
Python uses the symbols and symbol Combinations as delimiters in expressions, lists, dictionaries and strings following are the delimiters.

Literals
Literal is a raw data given in a variable or constant. In python, there are various types of literals.
1) Numeric
2) String
3) Boolean
1) Numeric Literals
Numeric literals consists of digits and are immutable (unchangeable). Numeric literals can belong to 3 different numerical types Integer, float and complex.
2) String literals
In python a string literal is a sequence of characters surrounded by quotes. Python supports single, double and triple quotes for a string. A character literal is a single character surrounded by single or double quotes. The value with triple- quote "' "' is used to give multi-line string literal.
3) Boolean literals
A Boolean literal can have any of the two values: True or False.
4) Escape sequences
In python strings, the backslash "\" is a special character, also called the "escape" character. It is used in representing certain white space character: "\t" is a tab, "\n" is a newline, and "\r is a carriage return. For Example to print the message "It's raining"
The python command is
>> print ("It \'s raining")
It's raining
Python supports the following escape sequence characters.

A script is a text file containing the Python statements. Python Scripts are reusable code. Once the script is created, it can be executed6again and again without retyping. The Scripts are editable
i) Creating Scripts in Python:
1. Choose File → New File or press Ctrl + N in Python shell window.

2. An untitled blank script text editor will be displayed on screen

3. Type the following code in script editor.
a = 100
b= 350
C = a + b
print ("The sum=", c)

ii) Saving Python script:
1. Choose File → Save or press Ctrl+S.

2. Now, Save As dialog box appears on the screen.

3. In the Sare As dialog box, select the location where you want to save your Python code, and type the File name in File Name box. Python files are by default saved will extension • py. Thus, while creating Python Scripts using Pyrhons script editor, no need to specify the file extension.
4. Hinallyiclick save button to save your python script.
iii) Exccuthon Python Script:
1. Choose Run → Run module or Press F5.

2. If your code has any error, it will be shown in red color in the IDLE window, and Python describes the type of error occurred. To correct the errors, go back to Script editor, make corrections, save the file using Ctrl +s or File → Save and execute il again.
3, For all error line code, the output will appear in the IDLL window of Python.