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Recitation 5 — Lists

Skills: 3​

Reading: 5.1, 5.2​

Working with Lists​

Here's some cafe sales data:

cafe-data = table: day, drinks-sold
    row: "Mon", 45
    row: "Tue", 30
    row: "Wed", 55
    row: "Thu", 40
    row: "Fri", 60
end

Extracting Lists from Tables​

Extract the drinks-sold column as a list using get-column. What does this list look like? How is it different from the original table?

Mathematical Operations on Lists​

You'll need to import the math and statistics libraries:

import math as M
import statistics as S

Using the extracted list, find:

  • The maximum number of drinks sold (use M.max)
  • The minimum number of drinks sold (use M.min)
  • The average daily sales (use S.mean)
  • The total weekly sales (use M.sum)

Creating List Literals​

Create these lists directly (without using a table):

  • A list of test scores: 85, 92, 78, 96, 88, 91
  • An empty list
  • A list of names: "Alice", "Bob", "Carol"

Using your test scores list, calculate:

  • The highest score (use M.max)
  • The average score (use S.mean)
  • The total of all scores (use M.sum)

Transforming Lists with Map​

You'll need to import the lists library:

import lists as L

Convert these Celsius temperatures to Fahrenheit: 0, 10, 20, 30, 40

The formula is: (celsius × 9/5) + 32

Use L.map with a function that applies this formula to each temperature.

Working with Student Grades​

Given these raw scores: 78, 85, 92, 67, 88, 94, 73, 81, 90, 86

Apply a 5-point curve to all scores using L.map with a lambda function that adds 5 to each score.

Then convert the curved scores to letter grades using L.map with a lambda function that checks the score ranges:

  • A: 90 and above
  • B: 80-89
  • C: 70-79
  • D: 60-69
  • F: below 60

How many students got each letter grade?

Finding Unique Values​

Use L.distinct to find all the unique letter grades that were assigned.

Filtering Lists​

Use L.filter with a lambda function to find all the passing scores (60 and above) from your curved scores list. How many students passed?

Wrap-Up​

When would you use a list instead of a table? What real-world data could you analyze using these list operations?