Exercise

Exercises: Variables and Data Types

These exercises are designed to help you practice working with variables and different data types in Python. Follow each step carefully and try to predict the output before running the code.

File Organization

To keep your work organized, we'll use the following file structure:

csf101-python_exercises/
│
├── basics/
│   ├── numbers.py
│   ├── strings.py
│   └── booleans.py
│
└── data_structures/
    ├── lists.py
    └── dictionaries.py

Create a new directory called python_exercises and navigate into it. Then, create two subdirectories: basics and data_structures.

Exercise 1: Working with Integers and Floats

File: basics/numbers.py

Create a new file called numbers.py in the basics directory and complete the following exercises in this file.

Create a variable age and assign it your age as an integer.
```
age = 25  # Replace with your actual age
print(age)
```
Expected output: 25
Create a variable height and assign it your height in meters as a float.
```
height = 1.75  # Replace with your actual height
print(height)
```
Expected output: 1.75
Calculate your age in days (assume 365 days per year) and store it in a variable age_in_days.
```
age_in_days = age * 365
print(age_in_days)
```
Expected output: 9125
Divide your age by 7 and print the result.
```
result = age / 7
print(result)
```
Expected output: 3.5714285714285716

Note: The result is a float, even though we started with integers.

Exercise 2: Working with Strings

File: basics/strings.py

Create a new file called strings.py in the basics directory and complete the following exercises in this file.

Create a variable name and assign it your full name as a string.
```
name = "John Doe"  # Replace with your actual name
print(name)
```
Expected output: John Doe
Use string concatenation to create a greeting message.
```
greeting = "Hello, " + name + "!"
print(greeting)
```
Expected output: Hello, John Doe!
Use f-strings to create the same greeting message.
```
greeting_f = f"Hello, {name}!"
print(greeting_f)
```
Expected output: Hello, John Doe!
Print the length of your name.
```
name_length = len(name)
print(name_length)
```
Expected output: 8

Warning: Remember that spaces count as characters too!

Exercise 3: Working with Booleans

File: basics/booleans.py

Create a new file called booleans.py in the basics directory and complete the following exercises in this file.

Create two boolean variables, is_student and is_employed, and assign them appropriate values.
```
is_student = True
is_employed = False
print(is_student, is_employed)
```
Expected output: True False
Use the and operator to check if you are both a student and employed.
```
is_student_and_employed = is_student and is_employed
print(is_student_and_employed)
```
Expected output: False
Use the or operator to check if you are either a student or employed.
```
is_student_or_employed = is_student or is_employed
print(is_student_or_employed)
```
Expected output: True

Exercise 4: Type Conversion

File: basics/type_conversion.py

Create a new file called type_conversion.py in the basics directory and complete the following exercises in this file.

Convert your age to a string and concatenate it with a message.

age = 25  # Use the same age as in numbers.py
age_str = str(age)
message = "I am " + age_str + " years old."
print(message)

Expected output: I am 25 years old.

Try to convert a string to an integer.
```
num_str = "42"
num_int = int(num_str)
print(num_int)
```
Expected output: 42
Now try to convert a non-numeric string to an integer.
```
non_num_str = "Hello"
try:
    non_num_int = int(non_num_str)
    print(non_num_int)
except ValueError as e:
    print(f"Error: {e}")
```
Expected output: Error: invalid literal for int() with base 10: 'Hello'

Note: This will raise a ValueError, which we catch and print.

Exercise 5: Working with Lists

File: data_structures/lists.py

Create a new file called lists.py in the data_structures directory and complete the following exercises in this file.

Create a list of your favorite fruits.
```
fruits = ["apple", "banana", "cherry"]
print(fruits)
```
Expected output: ['apple', 'banana', 'cherry']
Add a new fruit to your list using the append() method.
```
fruits.append("date")
print(fruits)
```
Expected output: ['apple', 'banana', 'cherry', 'date']
Access and print the second fruit in your list.
```
second_fruit = fruits[1]
print(second_fruit)
```
Expected output: banana

Warning: Remember that list indices start at 0!

Exercise 6: Working with Dictionaries

File: data_structures/dictionaries.py

Create a new file called dictionaries.py in the data_structures directory and complete the following exercises in this file.

Create a dictionary with information about yourself.

name = "John Doe"  # Use the same name as in strings.py
age = 25  # Use the same age as in numbers.py
height = 1.75  # Use the same height as in numbers.py
is_student = True  # Use the same value as in booleans.py

person_info = {
    "name": name,
    "age": age,
    "height": height,
    "is_student": is_student
}
print(person_info)

Expected output: {'name': 'John Doe', 'age': 25, 'height': 1.75, 'is_student': True}

Add your favorite color to the dictionary.
```
person_info["favorite_color"] = "blue"  # Replace with your actual favorite color
print(person_info)
```
Expected output: {'name': 'John Doe', 'age': 25, 'height': 1.75, 'is_student': True, 'favorite_color': 'blue'}
Try to access a key that doesn't exist in the dictionary.
```
try:
    print(person_info["weight"])
except KeyError as e:
    print(f"Error: {e}")
```
Expected output: Error: 'weight'

Note: This will raise a KeyError because 'weight' is not a key in our dictionary.

Congratulations!

Final Notes on File Organization

Keeping related concepts in the same directory (basics or data_structures) helps in organizing your learning process.
As you progress in your Python journey, you can add more directories for advanced topics (e.g., functions, classes, modules).
Always try to keep your code organized - it's a good habit that will help you as you work on larger projects.

Remember to run each file separately to see the output of your exercises. You can do this by navigating to the appropriate directory in your terminal and running python filename.py (e.g., python numbers.py).