assert: Raises error if predicate is FALSE in any columns selected

Description Usage Arguments Details Value Note See Also Examples

View source: R/assertions.R

Description

Meant for use in a data analysis pipeline, this function will just return the data it's supplied if there are no FALSEs when the predicate is applied to every element of the columns indicated. If any element in any of the columns, when applied to the predicate, is FALSE, then this function will raise an error, effectively terminating the pipeline early.

Usage

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assert(data, predicate, ..., success_fun = success_continue,
  error_fun = error_stop)

assert_(data, predicate, ..., .dots, success_fun = success_continue,
  error_fun = error_stop)

Arguments

data

A data frame

predicate

A function that returns FALSE when violated

...

Comma separated list of unquoted expressions. Uses dplyr's select to select columns from data.

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.

.dots

Use assert_() to select columns using standard evaluation.

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

verify insist assert_rows insist_rows

Examples

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# returns mtcars
assert(mtcars, not_na, vs)

# equivalent statements using standard evaluation
assert_(mtcars, not_na, "vs")
var <- "vs"
assert_(mtcars, not_na, var)

# return mtcars
assert(mtcars, not_na, mpg:carb)

# equivalent using standard evaluation
assert_(mtcars, not_na, "mpg:carb")


library(magrittr)                    # for piping operator

mtcars %>%
  assert(in_set(c(0,1)), vs)
  # anything here will run

## Not run: 
mtcars %>%
  assert(in_set(c(1, 2, 3, 4, 6)), carb)
  # the assertion is untrue so
  # nothing here will run
## End(Not run)


assertr documentation built on May 20, 2017, 1:54 a.m.
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