L1.1 Primitive Data Types

This lesson introduces primitive data types, which are the building blocks of all programs. You’ll learn how to identify and use these types effectively.

Key Terminology

• Integer (int): A whole number, positive, negative, or zero (e.g., 5, -10).

• Float (real): A number with a decimal point (e.g., 3.14, -2.7).

• Boolean (bool): A value that can only be True or False.

• Character (char): A single letter, number, or symbol (e.g., 'A', '7', '@').

• String: A sequence of characters (e.g., "Hello", "12345").

Key Ideas

Primitive Data Types:

Integer: Used for counting or indexing.

Example in Python:
age = 25

Float: Used for precise calculations or measurements.

Example:
pi = 3.14159

Boolean: Used in decision-making or comparisons.

Example:
is_raining = False

Character: Represents single symbols or letters.

Example in Python (as a string of length 1):
grade = 'A'

String: Used for textual data or identifiers.

Example:
name = "Alice"

L1.2 Compound Data Types

This lesson introduces compound data types, which combine multiple pieces of information into one structure.

Key Terminology

• Array: A collection of elements of the same type, stored in a fixed size. In Python these don't actually exist and we use Lists.

• List: A collection of elements that can grow or shrink dynamically.

• Record / Dictionary: A structure that groups related data of different types. In Python these are called dictionaries.

Key Ideas

Compound Data Types:

• List: Dynamic; allows adding and removing elements.

Example:

fruits = ["apple", "banana", "cherry"]

fruits.append("orange")

• Dictionary: Groups related fields of different data types (similar to a "row" in a table).

Example:
student = {"name": "Alice", "age": 16, "grade": "A"}

L1.3 Binary Representation of Data

This lesson explains how data is stored in a computer using binary (1s and 0s).

Key Terminology

• Binary: A base-2 number system (0 and 1) used by computers.

• Bit: A single binary digit (0 or 1).

• Byte: A group of 8 bits.

• ASCII: A system for encoding characters as binary numbers.

• Unicode: An encoding system for representing a wide range of characters.

Key Ideas

How Data Is Stored:

• Computers are extremely dense collections of tiny switches that turn on and off. This is how they process and store information. The on and off values are represented as 0 and 1 as in binary.

• Computers use binary to store all data (numbers, text, images, etc.).

• Each data type has a specific binary representation.

Binary Representation Examples:

1. Numbers:

   • Decimal 5 → Binary 101.

2. Characters:

   • 'A' in ASCII → Binary 01000001.

3. Images and Files:

   • Broken down into binary data for storage and processing.

L1.4 Casting and Type Conversion

This lesson focuses on how to change one data type into another in programming.

Key Terminology

• Casting: Converting one data type into another.

• Implicit Conversion: Automatic conversion performed by the programming language.

• Explicit Conversion: Manual conversion by the programmer.

Key Ideas

Why Convert Data Types?

• To perform operations on mixed data types. Many operations require a certain datatype otherwise will produce an error. For example, numbers inputed by a user through the keyboard will arrive in a program as a string, but if you need to do mathematical operations on these numbers they must be converted to an integer or float.

• To prepare data for specific uses (e.g., storing numbers as strings as with phone numbers).

Examples of Type Conversion in Python:

String to Integer:

num_str = "10"

num_int = int(num_str)

print(num_int + 5)  # Outputs: 15

Integer to Float:

num = 7

num_float = float(num)

Float to String:

pi = 3.14

pi_str = str(pi)