Lazy evaluation
summary
Explains that tidy eval is a metaprogramming toolkit implemented in rlang that preserves unquoted variable names by manipulating evaluation and data masks, and that it powers dplyr, ggplot2 and other tidyverse APIs. Shows a fixed lm/gapminder example that fails with plain NSE then works after capturing symbols with nquo + !! and using := for programmatic names, demonstrates when passing dots suffices and when you must use rlang, and confirms these patterns let grouped summarize and programmatic ggplot calls work reliably.
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chapters (18)
- 0:00Introduction
- 0:30What is tiny evaluation
- 1:12Things to learn first
- 3:08What is tidyeval
- 5:20Meta programming
- 6:03Nonstandard evaluation
- 7:03The bargain
- 8:32The problem
- 9:50LM example
- 12:30Tidy verse history
- 12:54Unquoted variable names
- 13:42The good news
- 14:13OurLang
- 14:38Scenarios
- 15:06Duplication
- 16:19Simple functions
- 17:01Example
- 18:16Resources
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