Convert between snake_case and camelCase

snake_camel.R

camel_to_snake <- function(x, case = c("lower", "upper")) {
        case <- match.arg(case)
        case_fun <- switch(case, lower = tolower, upper = toupper)
        case_fun(gsub("([a-z0-9])([A-Z]+)", "\\1_\\2", x))
}

snakeToCamel <- function(x) {
  x <- tolower(x)
  gsub("([a-z0-9]+)_([a-z0-9])", "\\1\\U\\2\\E", x, perl = TRUE)
}

testcamel <- c("camelCaseName", "camel1Case2Name")

camel_to_snake(testcamel)
#> [1] "camel_case_name"   "camel1_case2_name"

camel_to_snake(testcamel, case = "upper")
#> [1] "CAMEL_CASE_NAME"   "CAMEL1_CASE2_NAME"

testsnake <- c("snake_case_name", "SNAKE_CASE_NAME", "snake1_case2_name3")

snakeToCamel(testsnake)
#> [1] "snakeCaseName"    "snakeCaseName"    "snake1Case2Name3"

#' Created on 2018-03-22 by the [reprex package](http://reprex.tidyverse.org) (v0.2.0).