verify {assertr}

Raises error if expression is FALSE anywhere

Description

Meant for use in a data analysis pipeline, this function will just return the data it's supplied if all the logicals in the expression supplied are TRUE. If at least one is FALSE, this function will raise a error, effectively terminating the pipeline early

Usage

verify(
  data,
  expr,
  success_fun = success_continue,
  error_fun = error_stop,
  skip_chain_opts = FALSE,
  obligatory = FALSE,
  defect_fun = defect_append,
  description = NA
)

Arguments

data

A data frame, list, or environment

expr

A logical expression

success_fun

Function to call if assertion passes. Defaults to returning data.

error_fun

Function to call if assertion fails. Defaults to printing a summary of all errors.

skip_chain_opts

If TRUE, success_fun and error_fun are used even if assertion is called within a chain.

obligatory

If TRUE and assertion failed the data is marked as defective. For defective data, all the following rules are handled by defect_fun function.

defect_fun

Function to call when data is defective. Defaults to skipping assertion and storing info about it in special attribute.

description

Custom description of the rule. Is stored in result reports and data.

Details

For examples of possible choices for the success_fun and error_fun parameters, run help("success_and_error_functions")

Value

By default, the data is returned if predicate assertion is TRUE and and error is thrown if not. If a non-default success_fun or error_fun is used, the return values of these function will be returned.

Note

See vignette("assertr") for how to use this in context

See Also

assert insist

Examples

verify(mtcars, drat > 2)     # returns mtcars
## Not run: 
verify(mtcars, drat > 3)     # produces error
## End(Not run)


library(magrittr)            # for piping operator

## Not run: 
mtcars %>%
  verify(drat > 3) %>%
  # anything here will not run
## End(Not run)

mtcars %>%
  verify(nrow(mtcars) > 2)
  # anything here will run

alist <- list(a=c(1,2,3), b=c(4,5,6))
verify(alist, length(a) > 2)
verify(alist, length(a) > 2 && length(b) > 2)
verify(alist, a > 0 & b > 2)

## Not run: 
alist %>%
  verify(alist, length(a) > 5)
  # nothing here will run
## End(Not run)