Assert input is less than some maximum value — assert_less

Assert a number is less than a specified maximum value. To check all numbers in a vector / matrix are below a maximum value, see assert_all_less_than()

Usage

assert_less_than(
  x,
  maximum,
  msg = NULL,
  call = rlang::caller_env(),
  arg_name = NULL
)

Arguments

x: An object to check
maximum: The maximum value to compare against (number)
msg: A character string containing the error message to display if x is not less than the specified maximum value (string)
call: Only relevant when pooling assertions into multi-assertion helper functions. See cli_abort for details.
arg_name: Advanced use only. Name of the argument passed (default: NULL, will automatically extract arg_name).

Value

invisible(TRUE) if x is less than the specified maximum value, otherwise aborts with the error message specified by msg

Examples

try({
assert_less_than(1, 2) # Passes
assert_less_than(1, 2) # Passes
assert_less_than(c(1,2,3), 4) # Throws error (Must be a number)
assert_less_than('A', 1) # Throws error (Must be a number)
assert_less_than(3, 2, msg = "custom error message") # Throws custom error
})
#> Error in eval(expr, envir) : 
#>   'c(1, 2, 3)' is not a number! (length is 3, not 1)