Welcome to Day 7 of PythonForAI! Today, we will review all the topics we have covered during the week and then work on a project to consolidate our learning. The project will involve building a basic calculator that supports addition, subtraction, multiplication, and division.

## Table of Contents

## Review

### Day 1: Introduction to Python

**Setting Up Python**: Installing Python, Anaconda, and Jupyter Notebook.**Basic Syntax, Variables, and Data Types**: Understanding variables, data types (integers, floats, strings, booleans), and basic operations.

### Day 2: Control Structures

**Conditional Statements**: Using`if`

,`elif`

, and`else`

.**Loops**: Using`for`

and`while`

loops to iterate over sequences and perform repeated actions.

### Day 3: Functions

**Defining and Calling Functions**: Creating reusable code blocks with`def`

.**Function Arguments and Return Values**: Passing parameters and returning results from functions.

### Day 4: Data Structures

**Lists**: Ordered, mutable collections of items.**Tuples**: Ordered, immutable collections of items.**Dictionaries**: Unordered collections of key-value pairs.

### Day 5: Strings and File I/O

**String Manipulation**: Using methods to modify and format strings.**File I/O**: Reading from and writing to files using`open()`

and file methods.

### Day 6: Libraries and Modules

**Using Standard Libraries**: Importing and using libraries like`math`

and`datetime`

.**Creating Custom Modules**: Writing and importing your own Python modules.

## Project: Basic Calculator

### Project Requirements

We will build a simple calculator that performs addition, subtraction, multiplication, and division. The calculator will:

- Prompt the user to enter two numbers.
- Ask the user to select an operation (addition, subtraction, multiplication, division).
- Perform the selected operation and display the result.
- Handle invalid input and division by zero gracefully.

### Step-by-Step Implementation

#### Step 1: Define Functions for Each Operation

```
def add(a, b):
return a + b
def subtract(a, b):
return a - b
def multiply(a, b):
return a * b
def divide(a, b):
if b == 0:
return "Error: Division by zero"
return a / b
```

#### Step 2: Create the Calculator Function

```
def calculator():
print("Welcome to the Basic Calculator!")
while True:
try:
num1 = float(input("Enter the first number: "))
num2 = float(input("Enter the second number: "))
break
except ValueError:
print("Invalid input. Please enter numeric values.")
print("Select operation:")
print("1. Addition")
print("2. Subtraction")
print("3. Multiplication")
print("4. Division")
while True:
operation = input("Enter the number of the operation (1/2/3/4): ")
if operation in ['1', '2', '3', '4']:
if operation == '1':
result = add(num1, num2)
print(f"The result of addition: {num1} + {num2} = {result}")
elif operation == '2':
result = subtract(num1, num2)
print(f"The result of subtraction: {num1} - {num2} = {result}")
elif operation == '3':
result = multiply(num1, num2)
print(f"The result of multiplication: {num1} * {num2} = {result}")
elif operation == '4':
result = divide(num1, num2)
print(f"The result of division: {num1} / {num2} = {result}")
break
else:
print("Invalid selection. Please choose a valid operation (1/2/3/4).")
```

#### Step 3: Run the Calculator

```
if __name__ == "__main__":
calculator()
```

### Complete Code

Here’s the complete code for the basic calculator:

```
def add(a, b):
return a + b
def subtract(a, b):
return a - b
def multiply(a, b):
return a * b
def divide(a, b):
if b == 0:
return "Error: Division by zero"
return a / b
def calculator():
print("Welcome to the Basic Calculator!")
while True:
try:
num1 = float(input("Enter the first number: "))
num2 = float(input("Enter the second number: "))
break
except ValueError:
print("Invalid input. Please enter numeric values.")
print("Select operation:")
print("1. Addition")
print("2. Subtraction")
print("3. Multiplication")
print("4. Division")
while True:
operation = input("Enter the number of the operation (1/2/3/4): ")
if operation in ['1', '2', '3', '4']:
if operation == '1':
result = add(num1, num2)
print(f"The result of addition: {num1} + {num2} = {result}")
elif operation == '2':
result = subtract(num1, num2)
print(f"The result of subtraction: {num1} - {num2} = {result}")
elif operation == '3':
result = multiply(num1, num2)
print(f"The result of multiplication: {num1} * {num2} = {result}")
elif operation == '4':
result = divide(num1, num2)
print(f"The result of division: {num1} / {num2} = {result}")
break
else:
print("Invalid selection. Please choose a valid operation (1/2/3/4).")
if __name__ == "__main__":
calculator()
```

### Summary

Today, we reviewed all the topics covered during the week and applied our knowledge to build a basic calculator. This project helped reinforce concepts such as functions, user input, control structures, and error handling.

As you continue your Python journey, remember to practice regularly and explore new projects to apply what you’ve learned. The more you code, the more proficient you’ll become.

Feel free to leave any questions or comments below, and happy coding! 🐍🚀

### Additional Resources

### Frequently Asked Questions (FAQs)

**Q1: How can I handle more complex calculations with my calculator?**

You can extend your calculator by adding more functions for operations such as exponentiation, square root, and logarithms. You can also implement a more advanced user interface using libraries such as `tkinter`

for a graphical interface.

**Q2: What should I do if I encounter errors in my code?**

Debugging is an essential skill in programming. Use print statements to check variable values and understand the flow of your program. Python’s error messages are usually descriptive and can help you identify and fix issues.

**Q3: How can I make my code more efficient and readable?**

Follow best practices such as using descriptive variable names, writing modular code with functions, and adding comments to explain complex logic. Refactoring your code can also help improve efficiency and readability.

**Q4: What other projects can I work on to improve my Python skills?**

Consider working on projects such as a to-do list application, a simple web scraper, a personal diary app, or a small game. Choose projects that interest you and challenge you to learn new concepts.

**Q5: How can I continue learning Python after completing this course?**

Explore online tutorials, courses, and documentation. Participate in coding challenges on platforms like LeetCode, HackerRank, and Codewars. Join coding communities and collaborate on open-source projects.