CSE 1321 Module 1 Part 2: Data Types and Operators

Questions and Answers

Which of the following are types of Python built-in types?

Numerics (correct)

Mappings (correct)

Characters

Strings (correct)

What are integers?

Whole numbers of any size

What is a complex number in Python?

Numbers with a real and an imaginary part

In Python, string literals can span multiple lines without exceptions.

False Signup and view all the answers

What is the output of the expression print('Hello' + ' ' + 'there')?

Hello there Signup and view all the answers

Which escape sequence represents a newline?

\n Signup and view all the answers

What does the int() function do in Python?

Converts a value to an integer Signup and view all the answers

Which operator is used for division that produces a remainder?

% Signup and view all the answers

In Python, the equality operator is represented by '!='.

False Signup and view all the answers

To convert a floating-point number to an integer, you would use the ______ function.

int() Signup and view all the answers

Match the following Python data types with their descriptions:

Integer = Whole numbers of any size Float = Decimal numbers String = A sequence of characters Boolean = True or False values Signup and view all the answers

Study Notes

Data Types

Data types refer to the nature of data a variable is storing, influencing operations and memory usage.
Different programming languages have various built-in types.
Python's principal built-in types include:
- Numerics: Integers, floating-point numbers, complex numbers, and boolean values.
- Sequences: Lists, tuples, ranges, and strings.
- Mappings: Dictionaries.
- Others: Classes, instances, exceptions.

Numeric Types

Integers: Whole numbers of any size (e.g., 12).
Floating-point numbers: Decimal values with a precision of about 14 decimal places, including special cases "nan," "-inf," and "+inf."
Complex numbers: Comprise real and imaginary parts (e.g., 12+12j).
Booleans: Represent True or False, with the requirement of capitalization.

Strings

Strings are sequences of characters, allowing either single ('text') or double ("text") quotes.
Strings are immutable; assigning a new value creates a new string rather than altering the existing one.
Common string functions:
- len(): Returns character count.
- replace(): Exchanges part of the string.
- lower()/upper(): Adjusts string casing.
- isnumeric(): Validates if the string is numeric.
- split(): Splits strings into a list.

Printing & String Concatenation

String literals cannot span multiple lines (with exceptions).
The + operator concatenates strings with other data types, e.g., print("Hello" + " " + "there") results in "Hello there."

Escape Sequences

Escape sequences are used to insert special characters in strings:
- \b: Backspace
- \t: Tab
- \n: Newline
- \r: Carriage return
- \": Double quote
- \': Single quote
- \\: Backslash

Converting Between Types

To String: Use str(), compatible with most data types.
To Integer: Use int(), note that floats lose decimal precision.
To Floating-point: Use float(), integers gain decimal places.
To Complex: Use complex().

Comments

Comments are ignored by Python and serve as notes for developers.
Single-line comments use #, while multi-line comments are enclosed within triple quotes (''').

Expressions

Expressions are combinations of operators and operands that return a value and type after evaluation.
Operands can be literals, constants, or variables.

Arithmetic Operators

Key math operators:
- Addition (+): Can concatenate strings.
- Subtraction (-), Multiplication (*), Power (), Division (/), Floor Division (//), Modulus (%).**

Division & Modulus

Using / results in a decimal number, while // rounds down to the nearest whole number.
The modulus operator % returns the remainder of a division.

Type Awareness in Expressions

Data types impact which operations can be performed.
input() produces a string, and direct addition of strings and numbers is not allowed in Python.
Multiplying a string by an integer replicates the string, and any arithmetic operation between two integers results in an integer, except division.

Comparison Operators

Equality (==): Checks if values are equal.
Inequality (!=): Checks if values are not equal.
Comparison (>, <, >=, <=): Assess numerical and string relationships.

Description

This quiz covers key concepts from Module 1, Part 2 of CSE 1321, focusing on data types, expressions, and operators in Python. You will learn about various data types, how to concatenate strings, escape sequences, and the importance of operator precedence. Test your understanding of these foundational programming concepts and enhance your coding skills.