Page 173 - AI Ver 3.0 Class 11
P. 173
result_add = a + b
print("Addition:", result_add)
# Subtraction
result_sub = a - b
print("Subtraction:", result_sub)
Output:
Addition: 15
Subtraction: 5
Character Set
In Python, a character set refers to a collection of characters, typically defined by a specific encoding scheme, such as
ASCII (American Standard Code for Information Interchange) or Unicode. Each character in a character set is represented
by a unique code point.
A programming language’s character set refers to the permissible characters recognised by that language. When
discussing the Python programming language specifically, its character set encompasses all valid characters allowed for
scripting. These include:
• • Letters: Both uppercase (A-Z) and lowercase (a-z) letters.
• • Digits: All numerical digits from 0 to 9.
• • Special Symbols: Python accommodates various special symbols such as single quotes ('...'), double ("...“), semicolons
(;), colons (:), exclamation marks(!), tildes (~), at symbols(@), hash signs (#), dollar signs ($), percentage signs (%),
caret sign (^), backticks (`), ampersands (&), asterisks (*), parentheses (), underscores(_), plus signs(+), hyphens(-),
equal signs(=), curly braces {}, square brackets [], and backslashes(\).
• • Whitespace characters: Python recognises whitespace characters including tab spaces, blank spaces, newline
characters, and carriage return characters.
• • Others: Python supports the entirety of ASCII and Unicode characters, comprising the complete Python character
set.
Tokens
A token is the smallest unit of a program that has a meaning. Tokens in Python are fundamental elements of the language’s
syntax. They represent the building blocks of Python code, consisting of keywords, identifiers, literals, operators, and
punctuations. Understanding tokens is essential for comprehending Python’s lexical structure (basic syntax and set of
rules defining how Python programs are written) and parsing rules (guidelines used by a parser to analyse the structure
of code).
Python code is first divided into tokens during the lexical analysis phase of the interpretation process. These tokens are
then used by the parser to construct the abstract syntax tree (AST a tree representation of Python code that is used for
code analysis and manipulation), which is further processed to execute the code.
Tokens
Keywords Identifiers Literals Operators Punctuators
Python Programming 171

