In knapply/knapplyr: Tools to Facilitate Robust R Programming

knitr::opts_chunk$set(
  # collapse = TRUE,
  fig.align = "center",
  comment = "#>",
  fig.path = "man/figures/",
  message = FALSE,
  warning = FALSE
)
# options(width = 400)

`{knapplyr}`

Utility functions to facilitate robust R programming that are heavily-inspired by {purrr}.

{knapplyr} is meant to serve as a controlled environment for development and testing. The functions are not so much intended to be imported elsewhere, but instead to make it easy to have sane, tested, dependency-free utilities that can be easily used as internal, utility functions in other packages.

This is mainly for personal purposes, but if you'd like to use it, just add the /R/knapply-utils.R file to your package's /R folder. The functions will then be accessible just like any of your package's other functions.

`%||%` <- knapplyr:::`%||%`
`%{NULL}%` <- knapplyr:::`%{NULL}%`
`%{}%` <- knapplyr:::`%{}%`
`%{NA}%` <- knapplyr:::`%{NA}%`
`%{""}%` <- knapplyr:::`%{""}%`

Default-ers

library(dplyr)
foos <- c("`%||%`",
          "`%{NULL}%`",
          "`%{}%`",
          "`%{NA}%`",
          '`%{""}%`')

exs <- c('NULL %||% "common default NULL replacement"',
         'NULL %{NULL}% "alternate NULL replacement"',
         'character(0) %{}% "default empty replacement"',
         'NA %{NA}% "default NA replacement"',
         '"" %{""}% "default empty string replacement"')

tibble(`{knapply} Function` = foos, Example = exs) %>% 
  mutate(Result = glue::glue("`{purrr::map_chr(Example, ~ eval(parse(text = .x)))}`"),
         Example = glue::glue('`{Example}`')) %>% 
  knitr::kable(format = "html", escape = FALSE)

`.map*()`-ers

.map <- knapplyr:::.map
.map_chr <- knapplyr:::.map_chr
.map_lgl <- knapplyr:::.map_lgl
.map_int <- knapplyr:::.map_int
.map_dbl <- knapplyr:::.map_dbl

l1 <- list(a = 1:3, b = -1:-3)
l1
.map(l1, as.character)
.map_chr(l1, paste, collapse = ", ")
.map_int(l1, sum)
.map_dbl(l1, function(x) sum(x) * 2.5)
.map_lgl(l1, function(x) all(x > 0))

`.map2*()`-ers

.map2 <- knapplyr:::.map2
.map2_chr <- knapplyr:::.map2_chr
.map2_lgl <- knapplyr:::.map2_lgl
.map2_int <- knapplyr:::.map2_int
.map2_dbl <- knapplyr:::.map2_dbl

l2 <- list(a = 4:6, b = -4:-6)
l2
.map2(l1, l2, c)
.map2_chr(l1, l2, paste, collapse = " | ")
.map2_int(l1, l2, min)
.map2_dbl(l1, l2, function(x, y) sort(c(x, y))[[1L]])
.map2_lgl(l1, l2, function(x, y) all(c(x, y) > 0))