Skip to contents

Validate and return a value from a function

Source: R/interfacer.R
ireturn.Rd

This is intended to be used within a function to check the validity of a data frame being returned from a function against the provided iface specification.

Usage

ireturn(df, iface, .prune = FALSE)

Arguments

df

a dataframe - if missing then the first parameter of the calling function is assumed to be a dataframe.

iface

the interface specification that df should conform to.

.prune

get rid of excess columns that are not in the specification.

Value

a dataframe based on df with validity checks passed, data-types coerced, and correct grouping applied to conform to iface

Details

As checks on output files can be unnecessary they are only run in certain circumstances:

interfacer::ireturn() checks run if:

  • an option is set: options(interfacer.always_check=TRUE).

  • we are locally developing a package and running functions in smoke testing e.g. with devtools::load_all().

  • we are developing functions in the global environment.

  • we are running functions in a testthat or R CMD check.

  • we are running functions in a vignette during a R CMD check.

  • we are running functions in a R markdown file (e.g. vignette) interactively in RStudio.

checks are not run if:

  • package referencing interfacer::ireturn is installed from CRAN or r-universe

  • package referencing interfacer::ireturn is installed locally using devtools::install

  • vignette building directly using knitr (unless option is set in vignette).

  • vignette building using pkgdown::build_site().

Examples


input = iface(col_in = integer ~ "an integer column" )
output = iface(col_out = integer ~ "an integer column" )

x = function(df = input, ...) {
  df = ivalidate(...)
  tmp = df %>% dplyr::rename(col_out = col_in)
  ireturn(tmp, output)
  stop("not executed as function has returned")
}
x(tibble::tibble(col_in = c(1,2,3)))
#> interfacer: development mode active (local function).
#> This message is displayed once every 8 hours.
#> # A tibble: 3 × 1
#>   col_out
#> *   <int>
#> 1       1
#> 2       2
#> 3       3
output
#> A dataframe containing the following columns: 
#> * col_out (integer) - an integer column
#> Any grouping allowed.