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

Description

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()

Details

Note that strptime() has one idiosyncrasy to be aware of, namely that auto-detected ⁠format=⁠ is set by the first matching input, which means that a case like c(as.POSIXct("2024-01-01"), as.POSIXct("2024-01-01 01:02:03")) gives different results to as.POSIXct(c("2024-01-01", "2024-01-01 01:02:03")). This false positive is rare; a workaround where possible is to use consistent formatting, i.e., "2024-01-01 00:00:00" in the example.

Tags

consistency, efficiency, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "c(log10(x), log10(y), log10(z))",
  linters = inner_combine_linter()
)

# 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()
)