R: Tidy eval helpers

tidyeval {timetk} | R Documentation

## Tidy eval helpers

### Description

- `sym` creates a symbol from a string and `syms` creates a list of symbols from a character vector.

- `enquo` and `enquos` delay the execution of one or several function arguments. `enquo()` returns a single quoted expression, which is like a blueprint for the delayed computation. `enquos()` returns a list of such quoted expressions.

- `expr` quotes a new expression locally. It is mostly useful to build new expressions around arguments captured with `enquo()` or `enquos()`: `expr(mean(!!enquo(arg), na.rm = TRUE))`.

- `as_name` transforms a quoted variable name into a string. Supplying something else than a quoted variable name is an error.

  That's unlike `as_label` which also returns a single string but supports any kind of R object as input, including quoted function calls and vectors. Its purpose is to summarise that object into a single label. That label is often suitable as a default name.

  If you don't know what a quoted expression contains (for instance expressions captured with `enquo()` could be a variable name, a call to a function, or an unquoted constant), then use `as_label()`. If you know you have quoted a simple variable name, or would like to enforce this, use `as_name()`.

To learn more about tidy eval and how to use these tools, visit https://tidyeval.tidyverse.org and the Metaprogramming section of Advanced R.

[Package timetk version 2.6.0 Index]