In agoldst/litdata: R resources for Literary Data, Spring 2015

## ignore this fiddly bit and just leave it as is
knitr::opts_chunk$set(comment=NA, error=T, cache=T)
library("litdata")

Lists: Exercise

The following lines, which use str_detect, a function we haven't yet studied, derive a character vector with one element for each chapter of The Sheik.

# strip off all but the body text
body_ll <- sheik_ll[match("CHAPTER I", sheik_ll):
                    (match("THE END", sheik_ll) - 1)]
# find chapter heading indices:
# str_detect gives a logical vector telling us which lines
# match the pattern; which tells us the indices
chap_indices <- which(str_detect(body_ll, "^CHAPTER [IVX]"))

body_lc <- tolower(body_ll)

# initialize results vector
sheik_chaps <- character(length(chap_indices))

# tricky edge condition: contrive the last "chapter start"
# to be one past the last line
chap_indices <- c(chap_indices, length(body_ll) + 1)

for (j in seq_along(chap_indices[-length(chap_indices)])) {
    sheik_chaps[j] <- str_c(body_lc[chap_indices[j]:
                                   (chap_indices[j + 1] - 1)],
                           collapse=" ")
}

Now we split this up using our friend str_split:

sheik_chaps_words <- str_split(sheik_chaps, "\\W+")

sheik_chaps_words is a list.

Now write a for loop that counts the fraction of times "Arab" and "Diana" occur in each chapter, storing the results in two vectors.

arab <- numeric()
diana <- numeric()

# your for loop here

These lines will print out your results as occurrences per 10000 words:

For arab:

round(arab * 10000)

For diana:

round(diana * 10000)

Data Frames: Exercises

The logic of the query

Write down expressions that yield the following information by subscripting laureates.

1. What is the surname of the unique laureate born in Portugal?

# your expression here

1. What are the first names and surnames of the female laureates? (A single expression, yielding two columns of information.)

# your expression here

1. What are the full names of all the laureates who are either women or born in Sweden?

# your expression here

1. How many laureates died in a country other than the country of their birth? Derive also an expression for their names, countries of birth, and countries of death.

# your expression here

Sorting

1. Explain the relationship between a vector x and its ordering permutation order(x).

YOUR EXPLANATION HERE

1. Now we are going to exploit our special data-frame subscripting syntax. So we don't go crazy, let's work on a smaller table:

laur_small <- laureates[1:5, c("surname", "bornCountry", "gender", "year")]

Write an expression to sort this table alphabetically by surname.

# your expression for sorting laur_small here

1. Now sort it in reverse alphabetical order by country of birth.

# your expression for sorting laur_small here

1. Sort laur_small by gender and year of prize. You'll need two $ expressions.

# your expression for sorting laur_small here

1. Write an expression in terms of laureates to show first names, surnames, birth dates, and prize years of the five most recently-born laureates.

# your expression here

agoldst/litdata documentation built on May 10, 2019, 7:34 a.m.