Page 155 - Computer Science V2.0 Class 11

● Using different quotation marks to mark the beginning and end of a string
print("India')

print('India")
-----> the string should be enclosed within the same type of quotation marks
● Missing the closing parenthesis
print(10 -------> missing ')'
● Using incorrect case of a letter: Print / PRINT

PRINT('INDIA') -----> it should be print()

Let's Summarise

Ø The character set of Python includes lower case and uppercase alphabets, digits, symbols, and white space
characters, and some special characters like _ *$.,?. While naming the objects, the underscore character is
used like an alphabet.

Ø The smallest unit of a program is known as a token or a lexical unit.
Ø The tokens in Python are keywords, identifiers, literals, delimiters, and operators.
Ø Keywords are reserved words that have a specific meaning for the Python interpreter/compiler.
Ø Identifiers are the names or labels used to name a string, number, function, etc., in a program.

Ø The name should begin with an uppercase alphabet, lowercase alphabet, or underscore (_).
Ø An identifier cannot contain any special symbol except an underscore.
Ø A literal denotes a value, also called an object. Examples of literals include 23, 234.67, 'Hello', and "How are
you".
Ø Delimiters are symbols that are used to separate data items.
Ø An operator performs a specific operation on the specified values. For example, in the expression 23+4, the
operator + denotes the addition of the adjacent operands 23 and 4.
Ø A variable is a name that uniquely identifies an object.

Ø Variable are not declared explicitly in Python. They get associated with a type that is determined implicitly.
For example, consider the statements,

x = 23 #s1
x = 23.25 #s2
x = 'hello' #s3
In statements s1, s2, and s3, the variable x denotes an integer (23), a floating point (23.25), and a string object
('hello'), respectively.

Ø The nongraphic characters are represented using escape sequences.
Ø An escape sequence starts with a backslash (\) followed by one or more characters.
Ø Comments are statements that are ignored by the interpreter during the execution of the program.
Ø input() is used to accept data input from the user.
Ø print() is used to display the output on the standard output device, that is, the monitor.

Ø print() without any argument will print a blank line.

Basics of Python Programming 141