recycle: Strictly recycle function parameters

In interfacer: Define and Enforce Contracts for Dataframes as Function Parameters

Strictly recycle function parameters

Description

recycle is called within a function and ensures the parameters in the calling function are all the same length by repeating them using rep. This function alters the environment from which it is called. It is stricter than R recycling in that it will not repeat vectors other than length one to match the longer ones, and it throws more informative errors.

Usage

recycle(..., .min = 1, .env = rlang::caller_env())

Arguments

...	the variables to recycle
.min	the minimum length of the results (defaults to 1)
.env	the environment to recycle within.

Details

NULL values are not recycled, missing values are ignored.

Value

the length of the longest variable

Examples

testfn = function(a, b, c) {
  n = recycle(a,b,c)
  print(a)
  print(b)
  print(c)
  print(n)
}

testfn(a=c(1,2,3), b="needs recycling", c=NULL)
try(testfn(a=c(1,2,3), c=NULL))

testfn(a=character(), b=integer(), c=NULL)

# inconsistent to have a zero length and a non zero length
try(testfn(a=c("a","b"), b=integer(), c=NULL))

interfacer documentation built on April 4, 2025, 6:13 a.m.