PYTHON FUNDAMENTAL (CLASS - XI) PART - 1

PYTHON FUNDAMENTAL

CHAPTER -IV (PART - 1)

CLASS – XI

INTRODUCTION

In this chapter, we will learn about all basic elements that a python program can contain. You’ll be learning about Python’s basics like Character set, tokens, expressions, statements, simple input and output etc.

Python Character Set: A set of valid characters recognized by python. Python uses the traditional ASCII character set. The latest version recognizes the Unicode character set. The ASCII character set is a subset of the Unicode character set.

Letters: A-Z, a-z

Digits: 0 to 9

Special Symbols: Special symbol available over keyboard like +, -, ( ), *, & ^ %, !, @, # , etc.

White Space: Blank space, tab, carriage return, new line, form feed.

Other Characters: Python can process all ASCII and Unicode characters as part of data or literals.

Example:

a1 = ‘Informatics Practices’

b1 = ‘Computer Science

print (‘a1’, and, ‘b1’)

The output will be

Informatics Practices and Computer Science

raw_input(): Function in Python allow a user to give input to a program from a keyboard but in the form of string

Exampe:

name =int(input(“Enter your Name”))

age = int(input(“Enter your Age”))

per = float(input(“Enter your Percentage”))

Token

The smallest individual unit in a program is known as a Token or a lexical unit.

1. Keywords

2. Identifiers

3. Literals

4. Operators

5. Punctuators

Keywords: Reverse words of the compiler/interpreter which can’t be used as identifier.

and	Del	is	yield	not
as	For	pass	expect	try
assert	In	with	if	False
break	Or	else	nonlocal	True
class	While	global	return	None
continue	Elif	lambda	finally
def	From	raise	import

Identifiers: A Python identifier is a name used to identify a variable, function, class module, list, dictionaries or other objects.

Some important points for identifier:

An identifier starts with a letter A to Z or a to z or and underscore(_) followed by zero or more letters, underscore and digits (0 to 9).

Python does not allow special characters.

Identifier must not be a keywords of Python.

Python is a case sensitive programming language. Thus, Rollno and rollno are two different identifiers in Python.

Example of valid and invalid identifiers

Valid: Myname, file123, Y2ad, date_2, _no

Invalid: 2rno, break, my.name, data-cs

Literals: Literals in Python can be defined as number, text, or other data that represent values to be stored in variables. Python allows several kinds of literals: (i) String (ii) Numeric (iii) Boolean (iv) Special literal (v) Literal collections

Example of String Literals

name = ‘Shekhar’             ,              fname = “shekhar”

Example of Integer Literal (Numeric Literal)

age = 15

Example of Special Literals

name = None

Escape Sequence in Python

Escape Sequence	Description
\\	Backslash (\)
\’	Single quote (‘)
\”	Double quote(“)
\a	ASCII Bell (BEL)
\b	ASCII Backspace (BS)
\f	ASCII Formeed (FF)
\n	ASCII Linefeed (LF)
\r	ASCII Carriage Return (CR)
\t	ASCII Horizontal Tab (TAB)
\v	ASCII Vertical Tab (VT)
\ooo	Character with octal value
\xhh	Character with hex value hh

Note: This is the notes of Chapter -4 PYTHON FUNDAMENTAL (FIRST PART). It is important for every students. By the help of these notes students can prepare for their Exam.

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