Lists and Filtering Algorithms

[AlexRubio1]

Lists HW Hacks

Date: Apr 9, 2025
Read Time: 2 min
CSP Big Idea 2

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Popcorn Hacks

Popcorn Hack 1

A list allows for a lot of data to be stored in one place and allows for proper organization.
Some examples of lists are:

• Music playlists
• Shopping lists
• Online catalogs

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Popcorn Hack 2

The list would output "eraser", since it’s the second one in the index and third one in the overall list after deleting and adding a sharpener.

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Popcorn Hack 3

A real world example of a filtering algorithm is online shopping when you apply filters to the website to only get items that are within your budget.

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Homework Hacks

Python List and Procedures

items = ["soccer", "football", "cricket", "badminton", "softball"]

# List Procedure 1: Append - Adds a new item to the end of the list
items.append("basketball")  
# Now: ["soccer", "football", "cricket", "badminton", "softball", "basketball"]

# List Procedure 2: Remove - Removes a specific item from the list
items.remove("soccer")  
# Now: ["football", "cricket", "badminton", "softball", "basketball"]

# List Procedure 3: Insert - Inserts an item at a specific index
items.insert(3, "ballet")  
# Now: ["football", "cricket", "badminton", "ballet", "softball", "basketball"]

# Print final list to show result
print("Final List:", items)

##Output:

Final List: ['football', 'cricket', 'badminton', 'ballet', 'softball', 'basketball']


## Traversal Instructions

**Steps:**
1. Use a `for` loop to navigate through items.  
2. Traversal starts at index 0.  
3. Print each item.

for item in items:
    print("Current item:", item)

##output:
Current item: football  
Current item: cricket  
Current item: badminton  
Current item: ballet  
Current item: softball  
Current item: basketball  

## FIltering:

import pandas as pd

# Convert list to DataFrame
df = pd.DataFrame(items, columns=["Item"])

# Filter items containing the letter 'e'
filtered_df = df[df["Item"].str.contains("e")]

# Print the filtered list
print("Filtered Items (contain 'e'):")
print(filtered_df)


Final Reflection

Filtering algorithms and lists are used in real life for organizing and analyzing large amounts of data, such as:
	•	Sorting emails by unread status
	•	Recommending movies based on preferences

They help systems quickly search and process information, which increases customer satisfaction and improves the effectiveness of algorithms and code.