Block single-call magrittr pipes

Prefer using a plain call instead of a pipe with only one call, i.e. 1:10 %>% sum() should instead be sum(1:10). Note that calls in the first %>% argument count. rowSums(x) %>% max() is OK because there are two total calls (rowSums() and max()).

Usage

one_call_pipe_linter()

Details

Note also that un-"called" steps are not counted, since they should be calls (see pipe_call_linter()).

See also

• linters for a complete list of linters available in lintr.

• https://style.tidyverse.org/pipes.html#short-pipes

Tags

readability, style

Examples

# will produce lints
lint(
  text = "(1:10) %>% sum()",
  linters = one_call_pipe_linter()
)
#> <text>:1:1: warning: [one_call_pipe_linter] Avoid pipe %>% for expressions with only a single call.
#> (1:10) %>% sum()
#> ^~~~~~~~~~~~~~~~

lint(
  text = "DT %>% .[grp == 'a', sum(v)]",
  linters = one_call_pipe_linter()
)
#> <text>:1:1: warning: [one_call_pipe_linter] Avoid pipe %>% for expressions with only a single call.
#> DT %>% .[grp == 'a', sum(v)]
#> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

# okay
lint(
  text = "rowSums(x) %>% mean()",
  linters = one_call_pipe_linter()
)
#> ℹ No lints found.

lint(
  text = "DT[src == 'a', .N, by = grp] %>% .[N > 10]",
  linters = one_call_pipe_linter()
)
#> ℹ No lints found.

# assignment pipe is exempted
lint(
  text = "DF %<>% mutate(a = 2)",
  linters = one_call_pipe_linter()
)
#> ℹ No lints found.