scoped: Operate on a selection of variables
In YTLogos/dplyr: A Grammar of Data Manipulation

Description Arguments Details

The variants suffixed with _if, _at or _all apply an expression (sometimes several) to all variables within a specified subset. This subset can contain all variables (_all variants), a vars() selection (_at variants), or variables selected with a predicate (_if variants).

`.tbl`	A `tbl` object.
`.funs`	List of function calls generated by `funs()`, or a character vector of function names, or simply a function. Bare formulas are passed to `rlang::as_function()` to create purrr-style lambda functions. Note that these lambda prevent hybrid evaluation from happening and it is thus more efficient to supply functions like `mean()` directly rather than in a lambda-formula.
`.vars`	A list of columns generated by `vars()`, or a character vector of column names, or a numeric vector of column positions.
`.predicate`	A predicate function to be applied to the columns or a logical vector. The variables for which `.predicate` is or returns `TRUE` are selected. This argument is passed to `rlang::as_function()` and thus supports quosure-style lambda functions and strings representing function names.
`...`	Additional arguments for the function calls in `.funs`. These are evaluated only once, with explicit splicing.

The verbs with scoped variants are:

mutate(), transmute() and summarise(). See summarise_all().
filter(). See filter_all().
group_by(). See group_by_all().
rename() and select(). See select_all().
arrange(). See arrange_all()

There are three kinds of scoped variants. They differ in the scope of the variable selection on which operations are applied:

Verbs suffixed with _all() apply an operation on all variables.
Verbs suffixed with _at() apply an operation on a subset of variables specified with the quoting function vars(). This quoting function accepts select_vars() helpers like starts_with(). Instead of a vars() selection, you can also supply an integerish vector of column positions or a character vector of column names.
Verbs suffixed with _if() apply an operation on the subset of variables for which a predicate function returns TRUE. Instead of a predicate function, you can also supply a logical vector.