reduce.md
In purrr: Functional Programming Tools

empty input returns init or error

Code
  reduce(list())
Condition
  Error in `reduce()`:
  ! Must supply `.init` when `.x` is empty.

accumulate() does fail when simpification is required

Code
  accumulate(list(1, "a"), ~.y, .simplify = TRUE)
Condition
  Error in `accumulate()`:
  ! Can't combine `res[[1]]` <double> and `res[[2]]` <character>.

requires equal length vectors

Code
  reduce2(1:3, 1, `+`)
Condition
  Error in `reduce2()`:
  ! `.y` must have length 2, not 1.

requires init if `.x` is empty

Code
  reduce2(list())
Condition
  Error in `reduce2()`:
  ! Must supply `.init` when `.x` is empty.

right variants are retired

Code
  . <- reduce_right(1:3, c)
Condition
  Warning:
  `reduce_right()` was deprecated in purrr 0.3.0.
  i Please use the `.dir` argument of `reduce()` instead.
Code
  . <- reduce2_right(1:3, 1:2, c)
Condition
  Warning:
  `reduce2_right()` was deprecated in purrr 0.3.0.
  i Please use reverse your vectors and use `reduce2()` instead.
Code
  . <- accumulate_right(1:3, c)
Condition
  Warning:
  `accumulate_right()` was deprecated in purrr 0.3.0.
  i Please use the `.dir` argument of `accumulate()` instead.