Lab 3: Reading, inspecting, and writing data

Preparation

• Read/ annotate: Recipe #3. You can refer back to this document to help you at any point during this lab activity.

Objectives

• Read datasets from packages and from plain-text files
• Inspect and report characteristics of datasets
• Write datasets to a plain-text file (.csv or .tsv)

Instructions

Setup

1. Create a new R Markdown document. Title it "Lab #3" and provide add your name as the author.
2. Edit the front matter to have rendered R Markdown documents print pretty tabular datasets:

output: 
  html_document: 
    df_print: kable

3. Delete all the material below the front matter.
4. Add a code chunk directly below the header named 'setup' and add the code to load the following packages

• tidyverse
• tadr

Tasks

1. Create two level-1 header sections named: "Package data" and "Local data".
2. Follow the instructions that follow adding the relevant prose description and code chunks to the corresponding sections.

Remember:

• Add code comments (# code comments...) to your code lines to clarify what each step of your code does.
• Use Markdown syntax as necessary to format your responses
• You can use keyboard shortcuts inside code chunks/ the R Console such as
  • ⌥ - ('option + -') for the <- operator
  • ⇧⌘M ('shift + command + M') for the %>% operator
  • ⇥ ('tab') for code completion hints

Package data

You've already loaded the tadr package in the R session, now inspect the swda dataset. Apply your conceptual and R programming knowledge to address the following points:

• Describe the type of data that is represented in the swda dataset.
• Provide an overview ('glimpse' hint, hint) of the structure of the dataset (rows, columns, column types).
• Describe what the values in dialect_area represent.
• Subset the dataset and only select the doc_id, speaker_id, sex, and dialect_area columns. Assign the result to a new object (swda_sex_dialect).
• Show the first 10 rows of the swda_sex_dialect object. (Use slice_head.)
• Find out how many women versus men there are in this corpus. (Isolate the rows for which there are distinct value pairs for speaker_id and sex, group by sex, and then count the grouped rows.)
• Find out which dialect area has the most represented speakers in this corpus. (Isolate the rows for which there are distinct value pairs for speaker_id and dialect_area, group by dialect_area, and then counting the grouped rows. You may want to arrange the results so that the largest counts (n) appear in descending order.)

Local data

Now we are going to read a local dataset in plain-text format (endangered_languages.csv) into an R session. This dataset is in the data/ directory. Apply your conceptual and R programming knowledge to address the following points:

• Read the endangered_languages.csv dataset in your R session and assign it to a new object (end_langs).
• Provide an overview of the structure of the dataset (rows, columns, column types).
• Visit the source of this data. Describe what this dataset represents.
• Find the distinct values for the degree_of_endangerment column.
• Based on the source site, briefly describe what each value of degree_of_endangerment means.
• Filter the dataset to only return the 'Vulnerable' languages and assign the result to a new object (end_langs_vulnerable).
• With the new object (end_langs_vulnerable), identify the five 'Vulnerable' languages with the most speakers in the end_langs dataset.
• Write the end_langs_vulnerable object to a plain-text file (.csv or .tsv) in the data/ directory. Give it the same name as the object with the extension (.csv or .tsv).
• Copy and paste the following code into a new code chunk and provide some interpretation of what this plot shows or suggests.

end_langs_factor <-
  end_langs %>%
  mutate(degree_of_endangerment = factor(
    degree_of_endangerment,
    levels = c(
      "Vulnerable",
      "Definitely endangered",
      "Severely endangered",
      "Critically endangered",
      "Extinct"
    )
  ))
world_map <-
  map_data(map = "world") %>%
  filter(region != "Antarctica")

ggplot(data = world_map, aes(long, lat)) +
  geom_polygon(aes(group = group), fill = "white", color = "grey50") +
  geom_point(
    data = end_langs_factor,
    aes(x = longitude,
        y = latitude,
        color = degree_of_endangerment),
    size = .5
  ) +
  scale_color_discrete(direction = -1) +
  theme(legend.position = "bottom", legend.direction = "vertical") +
  labs(
    title = "Endangered Languages",
    y = "",
    x = "",
    color = "Degree of endangerment"
  )

Assessment

Add a section which describes your learning in this lab.

Some questions to consider:

• What did you learn?
• What was most/ least challenging?
• What resources did you consult?
• What more would you like to know about?

Submission

1. To prepare your lab report for submission on Canvas you will need to Knit your R Markdown document to PDF or Word.

• Note: you will have to add the front matter line to pretty-print tables under the pdf_document: or pdf_document2: (if you want cross-references to tables or figures) output.

output:
  pdf_document:
    df_print: kable

2. Download this file to your computer.
3. Go to the Canvas submission page for Lab #3 and submit your PDF/Word document as a 'File Upload'. Add any comments you would like to pass on to me about the lab in the 'Comments...' box in Canvas.