Require c() to be applied before relatively expensive vectorized functions

as.Date(c(a, b)) is logically equivalent to c(as.Date(a), as.Date(b)). The same equivalence holds for several other vectorized functions like as.POSIXct() and math functions like sin(). The former is to be preferred so that the most expensive part of the operation (as.Date()) is applied only once.

Usage

inner_combine_linter()

See also

linters for a complete list of linters available in lintr.

Tags

consistency, efficiency, readability

Examples

# will produce lints
lint(
  text = "c(log10(x), log10(y), log10(z))",
  linters = inner_combine_linter()
)
#> ::warning file=<text>,line=1,col=1::file=<text>,line=1,col=1,[inner_combine_linter] Combine inputs to vectorized functions first to take full advantage of vectorization, e.g., log10(c(x, y)) only runs the more expensive log10() once as compared to c(log10(x), log10(y)).

# okay
lint(
  text = "log10(c(x, y, z))",
  linters = inner_combine_linter()
)

lint(
  text = "c(log(x, base = 10), log10(x, base = 2))",
  linters = inner_combine_linter()
)