Homework 6: Much Ado About Lists!

Due: Tuesday March 10, 2020 at 9:00PM EST.

Handin

Due: Wednesday February 19, 2020 at 9:00PM EST.

Setup and Handin

Setup

Handin

Remember your resources!

The Assignment

This assignment draws on some basic ideas about analyzing text. For some of these problems, we will tell you whether to use the built-in list operations (like L.map and L.filter) or an explicit recursion function as we have been discussing in lecture.

A Literary Endeavor

The American West is a land of great discovery, and college is a time of spontaneous exploration. In pursuit of loot, Moses and Raj are investigating a ransacked saloon in Cody, WY when they stumble upon an old stone tablet. After some research, they find out that the tablet is a map to the long lost Wyoming Treasure! Help Moses and Raj crack the tablet’s text and find the secret treasure!

Task: Copy and paste this code into your file.

include shared-gdrive("shakespeare-text.arr", "1-XGIpbC13ItjxCh7WY14cCjfygk5wz5x") 
include shared-gdrive("cs111-2019.arr", "1YNg3-qHTjhd7koZVffPU6t032QX8vryg")
import lists as L
import math as M

book-text

Converting Text to a List of Words

Raj notices that the text on the tablet is from the first act of Shakespeare’s Much Ado About Nothing. This text is named book-text in the stencil code. You can see the text in full here. Raj needs your help to examine individual words in the text to analyze them for clues.

Task: Split book-text into a list of words, using the builtin string-split-all (in the Pyret String documentation). Name the resulting list of words/strings split-text.

Identifying Characters

Raj wants to compute the names of all the characters in the play. In the text, only the names of characters are in ALL CAPS. To find which of the words in split-text are characters’ names, we want a function that takes a list of Strings representing a play and returns a list of every String which is a name of a character in the play, without duplicates. The order of characters doesn’t matter.

Task: Write this function two ways, once using only built-in list operators and once with explicit recursion to locate the names (you can still use L.distinct as part of your recursive version). Name your versions find-charactersB (built-in version) and find-charactersR (recursive version).

Tallying Lines Per Character

The ALL-CAPS names mark each character’s spoken lines in the text. Raj wants to determine how many lines each character has, while also setting up his results for use in a later analysis.

Task: Write a function characters-table which takes in a list of Strings representing the names of characters in a play, and a list of Strings representing the text of the play. This function should return a Table with two columns: name and count. The name column should contain every character’s name in the order it was listed in the first input to your function. The count column should contain the number of times where that character’s name occurred.

Note: Do not use the built-in Table function count.

To construct the table here, use the following two functions, which are in the file you included at the top:

The following example shows how to build a table of room seating capacity:

new-table = create-table-with-col("room", [list: "CIT 101", "CIT 368"])
add-col(new-table, "seats", [list: 10, 65])

Note: you may solve this problem however you like, with recursion, built-in operators, or a mix of the two.

Average word length

Task: Write a function average-word-length which takes in a list of Strings and returns the average length of all words in the list, rounded to the nearest integer (use the built-in num-round).

Note: you may solve this problem however you like, with recursion, built-in operations, or a mix of the two.

Where’s Waldo??

Moses got a secret clue! “Waldo” is hidden somewhere in the “Much Ado About Nothing” text. But the clue doesn’t contain any hints about where to find Waldo.

Task: Write a function find-waldo which takes a String of text as input and returns the word that occurs immediately after “Waldo” in that text. Solve this problem using recursion rather than built-in operators.

For example, if the String is “the evening breeze Waldo rustled the leaves on the balcony”, then your function should return "rustled". It should always return the word immediately after Waldo. You may assume that “Waldo” will always be present exactly one time and it will not be the last word of the list.

For the most recent question, we only asked you to find the word directly after Waldo, but we might also have asked you to find the words directly before and after him (for our example above, this result would have been [list: "breeze", "rustled"]). What makes that version of the problem more challenging given what we’ve learned so far? What ideas do you have about how you might do that if we asked?

Task: Add a block comment underneath find-waldo answering these questions.

Waldo’s Snacks

Material for this question will be covered later this week.

Once Moses finds Waldo, he reveals that he has been hiding among the rustling leaves for years, waiting for someone to find him, and he is very hungry. Moses has a bag of mystery food supplies, but he doesn’t know which are good to give Waldo. He decides to build a datatype to help him track his food supplies and decide what to give Waldo.

Task: Create a datatype FoodItem. There is one constructor food that takes in food-name (a String), days-until-expiration (a Number) and food-group (a String). The food-group will be something like “fruit”, “vegetable”, “grain”, “dairy”, etc.

Task: Create a list ofFoodItems called food-list, containing three foods you think Waldo might enjoy (your choice).

Finally, write a function is-expired that takes one FoodItem and returns a boolean indicating whether the days-until-expiration is below zero.

Theme Song

I’m an Old Cowhand by Sonny Rollins

Brown University CSCI 0111 (Spring 2020)
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