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playground-workflow

Playground workflow

Last reviewed May 28, 2026 Content v20260528
Track mode
server_script
Means
Server runner
Reading
~2 min
Level
beginner

This lesson

This lesson teaches Playground workflow: the syntax, patterns, and safety habits you need before advancing in R.

Coroutines replace callback hell on Android and in Ktor—structured concurrency is interview-critical.

You will apply Playground workflow in contexts like: Research pipelines, Shiny dashboards, and statistical reporting.

Write R in the editor and click Run on server—the dev runner executes with Rscript; use print() or cat() and base R in playground snippets (tidyverse locally; LEARNING_RUNNER_ENABLED=true). Also use print() or cat(); install.packages() for dplyr/ggplot2 on your machine.

At the start of the track—complete before lessons that assume you understand the compiled playground.

Get the most from each lesson's Rscript editor—the same habits transfer to RStudio, VS Code with R extension, and CI running Rscript tests/testthat.R.

Recommended workflow

  1. Read the concept section before editing code.
  2. Click Run to execute with Rscript.
  3. Use print() for values and cat() for formatted output without auto quotes.
  4. Fix errors top to bottom—R stops at the first error in a statement.

What the runner can and cannot do

  • Can — single-file scripts with base R: print(), vectors, data.frame()
  • Needs local setuplibrary(dplyr), ggplot2, R Markdown, Shiny, renv projects

Compare workflows with Python and SQL tracks.

Important interview questions and answers

  1. Q: What prints output in R lessons?
    A: print() shows values; cat() writes strings without default quoting.
  2. Q: Can you load dplyr in the playground?
    A: Lessons teach dplyr in prose for local install—playground code uses base R equivalents.

Self-check

  1. What function prints without adding quotes around strings?
  2. What command runs a script locally?

Challenge

First Rscript run

  1. Click Run with the default code.
  2. Confirm output appears in the terminal.
  3. Add a second print() or cat() line with your name.

Done when: the terminal shows the default message and your custom line.

Challenge

Verify Rscript output

  1. Run the default program.
  2. Confirm output in the terminal.
  3. Add a deliberate syntax error and read the message.
  4. Fix and run again.

Done when: you see an error when appropriate and clean output after fixing.

Interview prep

What runs code in the playground?

Rscript executes your script—use print() and cat() for output.

Interview tip Lesson completion confidence

Can you explain this lesson in 30 seconds without reading notes?

Not saved yet.

Playground

Runs on the configured server runner (dev: npm run runner with LEARNING_RUNNER_ENABLED=true). Output appears below the editor.

Check yourself

Multiple choice — immediate feedback.

Discussion

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Starter discussion topics

  • Rscript errors?
  • Working directory?

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