1_list.py

# 📌 1. Append, Insert, Delete, and Remove Elements
# Definition: These operations allow adding or removing elements from a list.
# Usage: Used in dynamic data structures, inventory management, and real-time updates.
fruits = ["🍎", "🍌", "🍊", "🍇"]
print("🌟 Initial List:", fruits)

# Append 🍉 at the end
fruits.append("🍉")  # Adds to the end of the list
print("✅ After Append 🍉:", fruits)

# Insert 🍒 at index 2
fruits.insert(2, "🍒")  # Inserts at a specific index
print("✅ After Insert 🍒 at index 2:", fruits)

# Remove 🍌
fruits.remove("🍌")  # Removes the first occurrence of a value
print("❌ After Remove 🍌:", fruits)


# 📌 2. Reverse and Sort a List
# Definition: Reversing flips the order; sorting arranges items in ascending order.
# Usage: Used in ranking systems, leaderboards, and timeline ordering.
numbers = [10, 5, 8, 3, 2]
print("\n📊 Original Numbers:", numbers)

numbers.reverse()  # Reverses order
print("🔄 After Reverse:", numbers)

numbers.sort()  # Sorts in ascending order
print("📈 After Sorting:", numbers)


# 📌 3. Find Unique Values and Indexes
# Definition: Extracting unique elements and finding their positions.
# Usage: Used in filtering duplicate user IDs, tracking unique visitors.
nums = [5, 3, 5, 2, 3, 1, 4, 1]
print("\n🔍 Original List:", nums)

unique_values = list(set(nums))  # Removes duplicates
print("✨ Unique Values:", unique_values)

indices = [nums.index(i) for i in unique_values]  # Finds index of first occurrence
print("📍 Indices of Unique Values:", indices)


# 📌 4. Find Max and Min in a List
# Definition: Finds the highest and lowest values in a list.
# Usage: Used in financial applications (stock prices), leaderboards.
numbers = [10, 20, 30, 40, 50]
print("\n🎯 Numbers List:", numbers)

max_value = max(numbers)  # Finds maximum
min_value = min(numbers)  # Finds minimum
print("⬆️ Max Value:", max_value)
print("⬇️ Min Value:", min_value)


# 📌 5. Traversing a List (Accessing Elements)
# Definition: Iterating through elements in a list.
# Usage: Used in recommendation systems, iterating user profiles.
data = [23, 45, 'tyson', 3.14]
print("\n🚶‍♂️ Traversing the List:", end=" ")
for item in data:
    print(item, end=", ")


# 📌 6. Appending and Inserting Elements
# Definition: Adds elements at the end or a specific position.
# Usage: Used in dynamic content updates like social media feeds.
data.append(98)
print("\n\n✅ After Append 98:", data)

data.insert(2, 50)
print("✅ After Insert 50 at index 2:", data)


# 📌 7. Removing Elements by Index or Value
# Definition: Removes an element using its index or value.
# Usage: Used in cart management, removing selected items.
data.pop(2)  # Removes element at index 2
print("❌ After Pop at index 2:", data)

data.remove(45)  # Removes first occurrence of 45
print("❌ After Remove 45:", data)


# 📌 8. Merging Two Lists
# Definition: Combines two lists into one.
# Usage: Used in dataset merging, shopping cart updates.
list1 = [34, 56, 8, 7, 23]
list2 = [21, 34, 65, 34, 4]
merged_list = list1 + list2
print("\n🔗 Merged List:", merged_list)


# 📌 9. Sorting a List
# Definition: Arranges elements in ascending order.
# Usage: Used in ranking systems, sorted search results.
unsorted_list = [34, 45, 65, 2, 23, 43, 12, 90, 3]
unsorted_list.sort()
print("📈 Sorted List:", unsorted_list)


# 📌 10. Slicing a List
# Definition: Extracting a portion of the list.
# Usage: Used in pagination, fetching latest updates.
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
print("\n✂️ Original List:", numbers)

print("➡️ First 5 elements:", numbers[:5])
print("⬅️ Last 5 elements:", numbers[-5:])
print("↕️ Middle elements:", numbers[2:7])
print("↕️ Every 2nd element:", numbers[::2])


# 📌 11. List Comprehension (Creating a New List)
# Definition: Creating lists using concise syntax.
# Usage: Used in generating datasets, filtering data.
squares = [x**2 for x in range(1, 11)]
print("\n🔢 List of Squares (1-10):", squares)


# 📌 12. Copying a List (Shallow Copy)
# Definition: Creates a copy of a list.
# Usage: Used in preserving data before modifications.
original_list = [1, 2, 3, 4, 5]
copied_list = original_list.copy()
print("\n📋 Copied List:", copied_list)


# 📌 13. Extending a List (Adding Another List to It)
# Definition: Appends elements from another list.
# Usage: Used in dynamic data aggregation.
list1 = [10, 20, 30]
list2 = [40, 50, 60]
list1.extend(list2)
print("🔗 After Extending List1 with List2:", list1)


# 📌 14. Finding an Element in a List
# Definition: Returns the index of the first occurrence.
# Usage: Used in search functionalities.
items = ["apple", "banana", "cherry"]
index = items.index("banana")
print("\n🔎 Index of 'banana':", index)


# 📌 15. Counting Occurrences of an Element
# Definition: Counts how many times a value appears.
# Usage: Used in analytics, tracking item popularity.
nums = [1, 2, 3, 1, 2, 1, 4, 5]
count_ones = nums.count(1)
print("🧮 Count of 1 in List:", count_ones)


# 📌 16. Clearing a List (Removing All Elements)
# Definition: Removes all elements from a list.
# Usage: Used in resetting session data.
nums.clear()
print("🧹 After Clearing List:", nums)


# 📌 17. Checking Membership in a List
# Definition: Checks if an element exists in the list.
# Usage: Used in access control, keyword searches.
fruits = ["🍎", "🍌", "🍊", "🍇"]
print("\n🧐 Is 🍎 in list?", "🍎" in fruits)
print("🧐 Is 🍉 in list?", "🍉" in fruits)


#---------------Expected Output-----------------------

🌟 Initial List: ['🍎', '🍌', '🍊', '🍇']
✅ After Append 🍉: ['🍎', '🍌', '🍊', '🍇', '🍉']
✅ After Insert 🍒 at index 2: ['🍎', '🍌', '🍒', '🍊', '🍇', '🍉']
❌ After Remove 🍌: ['🍎', '🍒', '🍊', '🍇', '🍉']

📊 Original Numbers: [10, 5, 8, 3, 2]
🔄 After Reverse: [2, 3, 8, 5, 10]
📈 After Sorting: [2, 3, 5, 8, 10]

🔍 Original List: [5, 3, 5, 2, 3, 1, 4, 1]
✨ Unique Values: [1, 2, 3, 4, 5]
📍 Indices of Unique Values: [5, 3, 1, 6, 0]

🎯 Numbers List: [10, 20, 30, 40, 50]
⬆️ Max Value: 50
⬇️ Min Value: 10

🚶‍♂️ Traversing the List: 23, 45, tyson, 3.14, 
✅ After Append 98: [23, 45, 'tyson', 3.14, 98]
✅ After Insert 50 at index 2: [23, 45, 50, 'tyson', 3.14, 98]

🔗 Merged List: [34, 56, 8, 7, 23, 21, 34, 65, 34, 4]
📈 Sorted List: [2, 3, 12, 23, 34, 43, 45, 65, 90]

✂️ Original List: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
➡️ First 5 elements: [1, 2, 3, 4, 5]
⬅️ Last 5 elements: [6, 7, 8, 9, 10]
↕️ Middle elements: [3, 4, 5, 6, 7]
↕️ Every 2nd element: [1, 3, 5, 7, 9]

🔢 List of Squares (1-10): [1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

📋 Copied List: [1, 2, 3, 4, 5]

🔗 After Extending List1 with List2: [10, 20, 30, 40, 50, 60]

🔎 Index of 'banana': 1
🧮 Count of 1 in List: 3
🧹 After Clearing List: []

🧐 Is 🍎 in list? True
🧐 Is 🍉 in list? False