Reprex practice

Instructions

Below are two chunks of code that each throw an error. Your job isn’t to fix the code — it’s to turn each one into a reprex: reproducible, minimal, and self-contained.

For each example:

  1. Run the code and read the error.
  2. Strip it down to the smallest version that still produces the same error. Cut anything — columns, steps, arguments — that isn’t needed to trigger it.
  3. Make sure it’s self-contained: no object should be used before it’s created within the reprex itself.
  4. Use the reprex package to generate a clean, shareable version.
  5. Trade with a partner. Can they spot the bug just from reading your reprex — without ever seeing your original code?

Create a script in your day 9 folder called day9am-reprex-practice.R and work through both examples there.

library(tidyverse)
library(reprex)

Get the data

Download AS00601.csv and put it in a data/ subfolder inside your day 9 folder.

Data source: Gregory, S.V. and I. Arismendi. 2020. Aquatic Vertebrate Population Study in Mack Creek, Andrews Experimental Forest, 1987 to present ver 14. Environmental Data Initiative. https://doi.org/10.6073/pasta/7c78d662e847cdbe33584add8f809165

Read it in — this part works fine:

mack_creek_vertebrates <- read_csv("data/AS00601.csv")

Example 1

mack_creek_lengths <- mack_creek_vertebrates |>
  select(YEAR:SAMPLEDATE) |>
  filter(SECTION == "CC",
         !is.na(SPECIES)) |>
  summarize(mean_length_cm = mean(LENGTH1, na.rm = TRUE),
            sd_length_cm = sd(LENGTH1, na.rm = TRUE),
            .by = species)

Example 2

mack_creek_vertebrates |>
  filter(SPECIES == "ONCL") +
  ggplot(mapping = aes(x = LENGTH1, y = WEIGHT)) +
  geom_point() +
  scale_x_continuous("Cutthroat trout length (cm)") +
  scale_y_continuous("Weight (g)") +
  theme_minimal()

Making the reprex

Once your code is minimal and self-contained, copy it to your clipboard and run:

reprex()

reprex() runs your code in a fresh R session and copies a nicely formatted, ready-to-paste version — including the output and error — back to your clipboard. Paste it somewhere your partner can read it.

Tip

If reprex() runs cleanly with no error, that’s a clue: you may have accidentally fixed the bug (or cut something that mattered) while minimizing. Add back what you removed one piece at a time until the error returns.