Title:  Assertive Programming for R Analysis Pipelines 

Description:  Provides functionality to assert conditions that have to be met so that errors in data used in analysis pipelines can fail quickly. Similar to 'stopifnot()' but more powerful, friendly, and easier for use in pipelines. 
Authors:  Tony Fischetti [aut, cre] 
Maintainer:  Tony Fischetti <[email protected]> 
License:  MIT + file LICENSE 
Version:  3.0.1 
Built:  20241029 06:02:37 UTC 
Source:  https://github.com/tonyfischetti/assertr 
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.
assert( data, predicate, ..., success_fun = success_continue, error_fun = error_stop, skip_chain_opts = FALSE, obligatory = FALSE, defect_fun = defect_append, description = NA )
assert( data, predicate, ..., success_fun = success_continue, error_fun = error_stop, skip_chain_opts = FALSE, obligatory = FALSE, defect_fun = defect_append, description = NA )
data 
A data frame 
predicate 
A function that returns FALSE when violated 
... 
Comma separated list of unquoted expressions.
Uses dplyr's 
success_fun 
Function to call if assertion passes. Defaults to
returning 
error_fun 
Function to call if assertion fails. Defaults to printing a summary of all errors. 
skip_chain_opts 
If TRUE, 
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 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. 
For examples of possible choices for the success_fun
and
error_fun
parameters, run help("success_and_error_functions")
By default, the data
is returned if predicate assertion
is TRUE and and error is thrown if not. If a nondefault
success_fun
or error_fun
is used, the return
values of these function will be returned.
See vignette("assertr")
for how to use this in context
verify
insist
assert_rows
insist_rows
# returns mtcars assert(mtcars, not_na, vs) # return mtcars 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)
# returns mtcars assert(mtcars, not_na, vs) # return mtcars 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)
Meant for use in a data analysis pipeline, this function applies a function to a data frame that reduces each row to a single value. Then, a predicate function is applied to each of the row reduction values. If any of these predicate applications yield FALSE, this function will raise an error, effectively terminating the pipeline early. If there are no FALSEs, this function will just return the data that it was supplied for further use in later parts of the pipeline.
assert_rows( data, row_reduction_fn, predicate, ..., success_fun = success_continue, error_fun = error_stop, skip_chain_opts = FALSE, obligatory = FALSE, defect_fun = defect_append, description = NA )
assert_rows( data, row_reduction_fn, predicate, ..., success_fun = success_continue, error_fun = error_stop, skip_chain_opts = FALSE, obligatory = FALSE, defect_fun = defect_append, description = NA )
data 
A data frame 
row_reduction_fn 
A function that returns a value for each row of the provided data frame 
predicate 
A function that returns FALSE when violated 
... 
Comma separated list of unquoted expressions.
Uses dplyr's 
success_fun 
Function to call if assertion passes. Defaults to
returning 
error_fun 
Function to call if assertion fails. Defaults to printing a summary of all errors. 
skip_chain_opts 
If TRUE, 
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 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. 
For examples of possible choices for the success_fun
and
error_fun
parameters, run help("success_and_error_functions")
By default, the data
is returned if predicate assertion
is TRUE and and error is thrown if not. If a nondefault
success_fun
or error_fun
is used, the return
values of these function will be returned.
See vignette("assertr")
for how to use this in context
insist_rows
assert
verify
insist
# returns mtcars assert_rows(mtcars, num_row_NAs, within_bounds(0,2), mpg:carb) library(magrittr) # for piping operator mtcars %>% assert_rows(rowSums, within_bounds(0,2), vs:am) # anything here will run ## Not run: mtcars %>% assert_rows(rowSums, within_bounds(0,1), vs:am) # the assertion is untrue so # nothing here will run ## End(Not run)
# returns mtcars assert_rows(mtcars, num_row_NAs, within_bounds(0,2), mpg:carb) library(magrittr) # for piping operator mtcars %>% assert_rows(rowSums, within_bounds(0,2), vs:am) # anything here will run ## Not run: mtcars %>% assert_rows(rowSums, within_bounds(0,1), vs:am) # the assertion is untrue so # nothing here will run ## End(Not run)
The assertr package supplies a suite of functions designed to verify
assumptions about data early in an analysis pipeline.
See the assertr vignette or the documentation for more information
> vignette("assertr")
You may also want to read the documentation for the functions that
assertr
provides:
library(magrittr) # for the piping operator library(dplyr) # this confirms that #  that the dataset contains more than 10 observations #  that the column for 'miles per gallon' (mpg) is a positive number #  that the column for 'miles per gallon' (mpg) does not contain a datum # that is outside 4 standard deviations from its mean, and #  that the am and vs columns (automatic/manual and v/straight engine, # respectively) contain 0s and 1s only #  each row contains at most 2 NAs #  each row's mahalanobis distance is within 10 median absolute deviations of # all the distance (for outlier detection) mtcars %>% verify(nrow(.) > 10) %>% verify(mpg > 0) %>% insist(within_n_sds(4), mpg) %>% assert(in_set(0,1), am, vs) %>% assert_rows(num_row_NAs, within_bounds(0,2), everything()) %>% insist_rows(maha_dist, within_n_mads(10), everything()) %>% group_by(cyl) %>% summarise(avg.mpg=mean(mpg))
library(magrittr) # for the piping operator library(dplyr) # this confirms that #  that the dataset contains more than 10 observations #  that the column for 'miles per gallon' (mpg) is a positive number #  that the column for 'miles per gallon' (mpg) does not contain a datum # that is outside 4 standard deviations from its mean, and #  that the am and vs columns (automatic/manual and v/straight engine, # respectively) contain 0s and 1s only #  each row contains at most 2 NAs #  each row's mahalanobis distance is within 10 median absolute deviations of # all the distance (for outlier detection) mtcars %>% verify(nrow(.) > 10) %>% verify(mpg > 0) %>% insist(within_n_sds(4), mpg) %>% assert(in_set(0,1), am, vs) %>% assert_rows(num_row_NAs, within_bounds(0,2), everything()) %>% insist_rows(maha_dist, within_n_mads(10), everything()) %>% group_by(cyl) %>% summarise(avg.mpg=mean(mpg))
These functions are for starting and ending a sequence of assertr assertions and overriding the default behavior of assertr halting execution on the first error.
chain_start(data, store_success = FALSE) chain_end(data, success_fun = success_continue, error_fun = error_report)
chain_start(data, store_success = FALSE) chain_end(data, success_fun = success_continue, error_fun = error_report)
data 
A data frame 
store_success 
If TRUE each successful assertion is stored in chain. 
success_fun 
Function to call if assertion passes. Defaults to
returning 
error_fun 
Function to call if assertion fails. Defaults to printing a summary of all errors. 
For more information, read the relevant section in this package's
vignette using, vignette("assertr")
For examples of possible choices for the success_fun
and
error_fun
parameters, run help("success_and_error_functions")
library(magrittr) mtcars %>% chain_start() %>% verify(nrow(mtcars) > 10) %>% verify(mpg > 0) %>% insist(within_n_sds(4), mpg) %>% assert(in_set(0,1), am, vs) %>% chain_end()
library(magrittr) mtcars %>% chain_start() %>% verify(nrow(mtcars) > 10) %>% verify(mpg > 0) %>% insist(within_n_sds(4), mpg) %>% assert(in_set(0,1), am, vs) %>% chain_end()
This function will return a vector, with the same length as the number of rows of the provided data frame. Each element of the vector will be it's corresponding row with all of its values (one for each column) "pasted" together in a string.
col_concat(data, sep = "")
col_concat(data, sep = "")
data 
A data frame 
sep 
A string to separate the columns with (default: "") 
A vector of rows concatenated into strings
col_concat(mtcars) library(magrittr) # for piping operator # you can use "assert_rows", "is_uniq", and this function to # check if joint duplicates (across different columns) appear # in a data frame ## Not run: mtcars %>% assert_rows(col_concat, is_uniq, mpg, hp) # fails because the first two rows are jointly duplicates # on these two columns ## End(Not run) mtcars %>% assert_rows(col_concat, is_uniq, mpg, hp, wt) # ok
col_concat(mtcars) library(magrittr) # for piping operator # you can use "assert_rows", "is_uniq", and this function to # check if joint duplicates (across different columns) appear # in a data frame ## Not run: mtcars %>% assert_rows(col_concat, is_uniq, mpg, hp) # fails because the first two rows are jointly duplicates # on these two columns ## End(Not run) mtcars %>% assert_rows(col_concat, is_uniq, mpg, hp, wt) # ok
This function will return a vector, with the same length as the number of rows of the provided data frame. Each element of the vector will be logical value that states if any value from the row was duplicated in its column.
duplicates_across_cols(data, allow.na = FALSE)
duplicates_across_cols(data, allow.na = FALSE)
data 
A data frame 
allow.na 
TRUE if we allow NAs in data. Default FALSE. 
A logical vector.
df < data.frame(v1 = c(1, 1, 2, 3), v2 = c(4, 5, 5, 6)) duplicates_across_cols(df) library(magrittr) # for piping operator # you can use "assert_rows", "in_set", and this function to # check if specified variables set and all subsets are keys for the data. correct_df < data.frame(id = 1:5, sub_id = letters[1:5], work_id = LETTERS[1:5]) correct_df %>% assert_rows(duplicates_across_cols, in_set(FALSE), id, sub_id, work_id) # passes because each subset of correct_df variables is key ## Not run: incorrect_df < data.frame(id = 1:5, sub_id = letters[1:5], age = c(10, 20, 20, 15, 30)) incorrect_df %>% assert_rows(duplicates_across_cols, in_set(FALSE), id, sub_id, age) # fails because age is not key of the data (age == 20 is placed twice) ## End(Not run)
df < data.frame(v1 = c(1, 1, 2, 3), v2 = c(4, 5, 5, 6)) duplicates_across_cols(df) library(magrittr) # for piping operator # you can use "assert_rows", "in_set", and this function to # check if specified variables set and all subsets are keys for the data. correct_df < data.frame(id = 1:5, sub_id = letters[1:5], work_id = LETTERS[1:5]) correct_df %>% assert_rows(duplicates_across_cols, in_set(FALSE), id, sub_id, work_id) # passes because each subset of correct_df variables is key ## Not run: incorrect_df < data.frame(id = 1:5, sub_id = letters[1:5], age = c(10, 20, 20, 15, 30)) incorrect_df %>% assert_rows(duplicates_across_cols, in_set(FALSE), id, sub_id, age) # fails because age is not key of the data (age == 20 is placed twice) ## End(Not run)
This is used to generate id for each assertion error.
generate_id()
generate_id()
For single assertion that checks multiple columns, each error log is stored as a separate element. We provide the ID to allow detecting which errors come from the same assertion.
This function checks parent frame environment for existence of names. This is meant to be used with ‘assertr'’s 'verify' function to check for the existence of specific column names in a 'data.frame' that is piped to 'verify'. It can also work on a non'data.frame' list.
has_all_names(...)
has_all_names(...)
... 
A arbitrary amount of quoted names to check for 
TRUE if all names exist, FALSE if not
Other Name verification:
has_only_names()
verify(mtcars, has_all_names("mpg", "wt", "qsec")) library(magrittr) # for pipe operator ## Not run: mtcars %>% verify(has_all_names("mpgg")) # fails ## End(Not run) mpgg < "something" mtcars %>% verify(exists("mpgg")) # passes but big mistake ## Not run: mtcars %>% verify(has_all_names("mpgg")) # correctly fails ## End(Not run)
verify(mtcars, has_all_names("mpg", "wt", "qsec")) library(magrittr) # for pipe operator ## Not run: mtcars %>% verify(has_all_names("mpgg")) # fails ## End(Not run) mpgg < "something" mtcars %>% verify(exists("mpgg")) # passes but big mistake ## Not run: mtcars %>% verify(has_all_names("mpgg")) # correctly fails ## End(Not run)
This is meant to be used with ‘assertr'’s 'verify' function to check for the existence of a specific column class in a 'data.frame' that is piped to 'verify'.
has_class(..., class)
has_class(..., class)
... 
An arbitrary amount of quoted column names to check for 
class 
Expected class for chosen columns. 
TRUE if all classes are correct, FALSE if not
verify(mtcars, has_class("mpg", "wt", class = "numeric")) library(magrittr) # for pipe operator ## Not run: mtcars %>% verify(has_class("mpg", class = "character")) # fails ## End(Not run)
verify(mtcars, has_class("mpg", "wt", class = "numeric")) library(magrittr) # for pipe operator ## Not run: mtcars %>% verify(has_class("mpg", class = "character")) # fails ## End(Not run)
This function checks parent frame environment for a specific set of names; if more columns are present than those specified, an error is raised.
has_only_names(...)
has_only_names(...)
... 
A arbitrary amount of quoted names to check for 
This is meant to be used with ‘assertr'’s 'verify' function to check for the existence of specific column names in a 'data.frame' that is piped to 'verify'. It can also work on a non'data.frame' list.
TRUE is all names exist, FALSE if not
Other Name verification:
has_all_names()
# The last two columns names are switched in order, but all column names are # present, so it passes. verify( mtcars, has_only_names(c( "mpg", "cyl", "disp", "hp", "drat", "wt", "qsec", "vs", "am", "carb", "gear" )) ) # More than one set of character strings can be provided. verify( mtcars, has_only_names( c("mpg", "cyl", "disp", "hp", "drat", "wt", "qsec", "vs", "am"), c("carb", "gear") ) ) ## Not run: # The some columns are missing, so it fails. verify(mtcars, has_only_names("mpg")) ## End(Not run)
# The last two columns names are switched in order, but all column names are # present, so it passes. verify( mtcars, has_only_names(c( "mpg", "cyl", "disp", "hp", "drat", "wt", "qsec", "vs", "am", "carb", "gear" )) ) # More than one set of character strings can be provided. verify( mtcars, has_only_names( c("mpg", "cyl", "disp", "hp", "drat", "wt", "qsec", "vs", "am"), c("carb", "gear") ) ) ## Not run: # The some columns are missing, so it fails. verify(mtcars, has_only_names("mpg")) ## End(Not run)
This function returns a predicate function that will take a single
value and return TRUE if the value is a member of the set of objects
supplied. This doesn't actually check the membership of anything–it
only returns a function that actually does the checking when called
with a value. This is a convenience function meant to return a
predicate function to be used in an assertr
assertion.
You can use the 'inverse' flag (default FALSE) to check if the
arguments are NOT in the set.
in_set(..., allow.na = TRUE, inverse = FALSE)
in_set(..., allow.na = TRUE, inverse = FALSE)
... 
objects that make up the set 
allow.na 
A logical indicating whether NAs (including NaNs) should be permitted (default TRUE) 
inverse 
A logical indicating whether it should test if arguments are NOT in the set 
A function that takes one value and returns TRUE
if the value is in the set defined by the
arguments supplied by in_set
and FALSE
otherwise
predicate < in_set(3,4) predicate(4) ## is equivalent to in_set(3,4)(3) # inverting the function works thusly... in_set(3, 4, inverse=TRUE)(c(5, 2, 3)) # TRUE TRUE FALSE # the remainder of division by 2 is always 0 or 1 rem < 10 %% 2 in_set(0,1)(rem) ## this is meant to be used as a predicate in an assert statement assert(mtcars, in_set(3,4,5), gear) ## or in a pipeline, like this was meant for library(magrittr) mtcars %>% assert(in_set(3,4,5), gear) %>% assert(in_set(0,1), vs, am)
predicate < in_set(3,4) predicate(4) ## is equivalent to in_set(3,4)(3) # inverting the function works thusly... in_set(3, 4, inverse=TRUE)(c(5, 2, 3)) # TRUE TRUE FALSE # the remainder of division by 2 is always 0 or 1 rem < 10 %% 2 in_set(0,1)(rem) ## this is meant to be used as a predicate in an assert statement assert(mtcars, in_set(3,4,5), gear) ## or in a pipeline, like this was meant for library(magrittr) mtcars %>% assert(in_set(3,4,5), gear) %>% assert(in_set(0,1), vs, am)
Meant for use in a data analysis pipeline, this function applies a predicate generating function to each of the columns indicated. It will then use these predicates to check every element of those columns. If any of these predicate applications yield FALSE, this function will raise an error, effectively terminating the pipeline early. If there are no FALSES, this function will just return the data that it was supplied for further use in later parts of the pipeline.
insist( data, predicate_generator, ..., success_fun = success_continue, error_fun = error_stop, skip_chain_opts = FALSE, obligatory = FALSE, defect_fun = defect_append, description = NA )
insist( data, predicate_generator, ..., success_fun = success_continue, error_fun = error_stop, skip_chain_opts = FALSE, obligatory = FALSE, defect_fun = defect_append, description = NA )
data 
A data frame 
predicate_generator 
A function that is applied to each of the column vectors selected. This will produce, for every column, a true predicate function to be applied to every element in the column vectors selected 
... 
Comma separated list of unquoted expressions.
Uses dplyr's 
success_fun 
Function to call if assertion passes. Defaults to
returning 
error_fun 
Function to call if assertion fails. Defaults to printing a summary of all errors. 
skip_chain_opts 
If TRUE, 
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 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. 
For examples of possible choices for the success_fun
and
error_fun
parameters, run help("success_and_error_functions")
By default, the data
is returned if dynamically created
predicate assertion is TRUE and and error is thrown if not. If a
nondefault success_fun
or error_fun
is used, the
return values of these function will be returned.
See vignette("assertr")
for how to use this in context
assert
verify
insist_rows
assert_rows
insist(iris, within_n_sds(3), Sepal.Length) # returns iris library(magrittr) iris %>% insist(within_n_sds(4), Sepal.Length:Petal.Width) # anything here will run ## Not run: iris %>% insist(within_n_sds(3), Sepal.Length:Petal.Width) # datum at index 16 of 'Sepal.Width' vector is (4.4) # is outside 3 standard deviations from the mean of Sepal.Width. # The check fails, raises a fatal error, and the pipeline # is terminated so nothing after this statement will run ## End(Not run)
insist(iris, within_n_sds(3), Sepal.Length) # returns iris library(magrittr) iris %>% insist(within_n_sds(4), Sepal.Length:Petal.Width) # anything here will run ## Not run: iris %>% insist(within_n_sds(3), Sepal.Length:Petal.Width) # datum at index 16 of 'Sepal.Width' vector is (4.4) # is outside 3 standard deviations from the mean of Sepal.Width. # The check fails, raises a fatal error, and the pipeline # is terminated so nothing after this statement will run ## End(Not run)
Meant for use in a data analysis pipeline, this function applies a function to a data frame that reduces each row to a single value. Then, a predicate generating function is applied to row reduction values. It will then use these predicates to check each of the row reduction values. If any of these predicate applications yield FALSE, this function will raise an error, effectively terminating the pipeline early. If there are no FALSEs, this function will just return the data that it was supplied for further use in later parts of the pipeline.
insist_rows( data, row_reduction_fn, predicate_generator, ..., success_fun = success_continue, error_fun = error_stop, skip_chain_opts = FALSE, obligatory = FALSE, defect_fun = defect_append, description = NA )
insist_rows( data, row_reduction_fn, predicate_generator, ..., success_fun = success_continue, error_fun = error_stop, skip_chain_opts = FALSE, obligatory = FALSE, defect_fun = defect_append, description = NA )
data 
A data frame 
row_reduction_fn 
A function that returns a value for each row of the provided data frame 
predicate_generator 
A function that is applied to the results of the row reduction function. This will produce, a true predicate function to be applied to every element in the vector that the row reduction function returns. 
... 
Comma separated list of unquoted expressions.
Uses dplyr's 
success_fun 
Function to call if assertion passes. Defaults to
returning 
error_fun 
Function to call if assertion fails. Defaults to printing a summary of all errors. 
skip_chain_opts 
If TRUE, 
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 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. 
For examples of possible choices for the success_fun
and
error_fun
parameters, run help("success_and_error_functions")
By default, the data
is returned if dynamically created
predicate assertion is TRUE and and error is thrown if not. If a
nondefault success_fun
or error_fun
is used, the
return values of these function will be returned.
See vignette("assertr")
for how to use this in context
insist
assert_rows
assert
verify
# returns mtcars insist_rows(mtcars, maha_dist, within_n_mads(30), mpg:carb) library(magrittr) # for piping operator mtcars %>% insist_rows(maha_dist, within_n_mads(10), vs:am) # anything here will run ## Not run: mtcars %>% insist_rows(maha_dist, within_n_mads(1), everything()) # the assertion is untrue so # nothing here will run ## End(Not run)
# returns mtcars insist_rows(mtcars, maha_dist, within_n_mads(30), mpg:carb) library(magrittr) # for piping operator mtcars %>% insist_rows(maha_dist, within_n_mads(10), vs:am) # anything here will run ## Not run: mtcars %>% insist_rows(maha_dist, within_n_mads(1), everything()) # the assertion is untrue so # nothing here will run ## End(Not run)
This function is meant to take only a vector. It relies heavily on
the duplicated
function where it can be thought of as
the inverse. Where this function differs, though–besides being only
meant for one vector or column–is that it marks the first occurrence
of a duplicated value as "non unique", as well.
is_uniq(..., allow.na = FALSE)
is_uniq(..., allow.na = FALSE)
... 
One or more vectors to check for unique combinations of elements 
allow.na 
A logical indicating whether NAs should be preserved as missing values in the return value (FALSE) or if they should be treated just like any other value (TRUE) (default is FALSE) 
A vector of the same length where the corresponding element is TRUE if the element only appears once in the vector and FALSE otherwise
is_uniq(1:10) is_uniq(c(1,1,2,3), c(1,2,2,3)) ## Not run: # returns FALSE where a "5" appears is_uniq(c(1:10, 5)) ## End(Not run) library(magrittr) ## Not run: # this fails 4 times mtcars %>% assert(is_uniq, qsec) ## End(Not run) # to use the version of this function that allows NAs in `assert`, # you can use a lambda/anonymous function like so: mtcars %>% assert(function(x){is_uniq(x, allow.na=TRUE)}, qsec)
is_uniq(1:10) is_uniq(c(1,1,2,3), c(1,2,2,3)) ## Not run: # returns FALSE where a "5" appears is_uniq(c(1:10, 5)) ## End(Not run) library(magrittr) ## Not run: # this fails 4 times mtcars %>% assert(is_uniq, qsec) ## End(Not run) # to use the version of this function that allows NAs in `assert`, # you can use a lambda/anonymous function like so: mtcars %>% assert(function(x){is_uniq(x, allow.na=TRUE)}, qsec)
This function will return a vector, with the same length as the number of rows of the provided data frame, corresponding to the average mahalanobis distances of each row from the whole data set.
maha_dist(data, keep.NA = TRUE, robust = FALSE, stringsAsFactors = FALSE)
maha_dist(data, keep.NA = TRUE, robust = FALSE, stringsAsFactors = FALSE)
data 
A data frame 
keep.NA 
Ensure that every row with missing data remains NA in the output? TRUE by default. 
robust 
Attempt to compute mahalanobis distance based on robust covariance matrix? FALSE by default 
stringsAsFactors 
Convert nonfactor string columns into factors? FALSE by default 
This is useful for finding anomalous observations, rowwise.
It will convert any categorical variables in the data frame into numerics
as long as they are factors. For example, in order for a character
column to be used as a component in the distance calculations, it must
either be a factor, or converted to a factor by using the
stringsAsFactors
parameter.
A vector of observationwise mahalanobis distances.
maha_dist(mtcars) maha_dist(iris, robust=TRUE) library(magrittr) # for piping operator library(dplyr) # for "everything()" function # using every column from mtcars, compute mahalanobis distance # for each observation, and ensure that each distance is within 10 # median absolute deviations from the median mtcars %>% insist_rows(maha_dist, within_n_mads(10), everything()) ## anything here will run
maha_dist(mtcars) maha_dist(iris, robust=TRUE) library(magrittr) # for piping operator library(dplyr) # for "everything()" function # using every column from mtcars, compute mahalanobis distance # for each observation, and ensure that each distance is within 10 # median absolute deviations from the median mtcars %>% insist_rows(maha_dist, within_n_mads(10), everything()) ## anything here will run
This is the inverse of is.na
. This is a convenience
function meant to be used as a predicate in an assertr
assertion.
not_na(x, allow.NaN = FALSE)
not_na(x, allow.NaN = FALSE)
x 

allow.NaN 
A logical indicating whether NaNs should be allowed (default FALSE) 
A vector of the same length that is TRUE when the element is not NA and FALSE otherwise
not_na(NA) not_na(2.8) not_na("tree") not_na(c(1, 2, NA, 4))
not_na(NA) not_na(2.8) not_na("tree") not_na(c(1, 2, NA, 4))
This function will return a vector, with the same length as the number of rows of the provided data frame, corresponding to the number of missing values in each row
num_row_NAs(data, allow.NaN = FALSE)
num_row_NAs(data, allow.NaN = FALSE)
data 
A data frame 
allow.NaN 
Treat NaN like NA (by counting it). FALSE by default 
A vector of number of missing values in each row
num_row_NAs(mtcars) library(magrittr) # for piping operator library(dplyr) # for "everything()" function # using every column from mtcars, make sure there are at most # 2 NAs in each row. If there are any more than two, error out mtcars %>% assert_rows(num_row_NAs, within_bounds(0,2), everything()) ## anything here will run
num_row_NAs(mtcars) library(magrittr) # for piping operator library(dplyr) # for "everything()" function # using every column from mtcars, make sure there are at most # 2 NAs in each row. If there are any more than two, error out mtcars %>% assert_rows(num_row_NAs, within_bounds(0,2), everything()) ## anything here will run
'print' method for class "assertr_assert_error" This prints the error message and the entire twocolumn 'data.frame' holding the indexes and values of the offending data.
## S3 method for class 'assertr_assert_error' print(x, ...)
## S3 method for class 'assertr_assert_error' print(x, ...)
x 
An assertr_assert_error object 
... 
Further arguments passed to or from other methods 
'print' method for class "assertr_defect" This prints the defect message along with columns that were checked.
## S3 method for class 'assertr_defect' print(x, ...)
## S3 method for class 'assertr_defect' print(x, ...)
x 
An assertr_defect object 
... 
Further arguments passed to or from other methods 
'print' method for class "assertr_success" This prints the success message along with columns that were checked.
## S3 method for class 'assertr_success' print(x, ...)
## S3 method for class 'assertr_success' print(x, ...)
x 
An assertr_success object 
... 
Further arguments passed to or from other methods 
'summary' method for class "assertr_verify_error"
## S3 method for class 'assertr_verify_error' print(x, ...)
## S3 method for class 'assertr_verify_error' print(x, ...)
x 
An assertr_verify_error object. 
... 
Further arguments passed to or from other methods 
The behavior of functions like assert
, assert_rows
,
insist
, insist_rows
, verify
when the assertion
passes or fails is configurable via the success_fun
and error_fun
parameters, respectively.
The success_fun
parameter takes a function that takes
the data passed to the assertion function as a parameter. You can
write your own success handler function, but there are a few
provided by this package:
success_continue
 just returns the data that was
passed into the assertion function
success_logical
 returns TRUE
success_append
 returns the data that was
passed into the assertion function
but also stores basic information about
verification result
success_report
 When success results are stored, and each
verification ended up with success prints
summary of all successful validations
success_df_return
 When success results are stored, and each
verification ended up with success prints
data.frame with verification results
The error_fun
parameter takes a function that takes
the data passed to the assertion function as a parameter. You can
write your own error handler function, but there are a few
provided by this package:
error_stop
 Prints a summary of the errors and
halts execution.
error_report
 Prints all the information available
about the errors in a "tidy"
data.frame
(including information
such as the name of the predicate used,
the offending value, etc...) and halts
execution.
error_append
 Attaches the errors to a special
attribute of data
and returns the data. This is chiefly
to allow assertr errors to be accumulated in a pipeline so that
all assertions can have a chance to be checked and so that all
the errors can be displayed at the end of the chain.
error_return
 Returns the raw object containing all
the errors
error_df_return
 Returns a "tidy" data.frame
containing all the errors, including informations such as
the name of the predicate used, the offending value, etc...
error_logical
 returns FALSE
just_warn
 Prints a summary of the errors but does
not halt execution, it just issues a warning.
warn_report
 Prints all the information available
about the errors but does not halt execution, it just issues a warning.
defect_report
 For single rule and defective data it displays
short info about skipping current assertion. For chain_end
sums
up all skipped rules for defective data.
defect_df_return
 For single rule and defective data it returns
info data.frame about skipping current assertion. For chain_end
returns all skipped rules info data.frame for defective data.
You may find the third type of data verification result. In a scenario when validation rule was obligatory (obligatory = TRUE) in order to execute the following ones we may want to skip them and register that fact. In order to do this there are three callbacks reacting to defective data:
defect_report
 For single rule and defective data it displays
short info about skipping current assertion.
defect_df_return
 For single rule and defective data it returns
info data.frame about skipping current assertion.
defect_append
 Appends info about skipped rule due to data
defect into one of data attributes. Rules skipped on defective data, or its summary, can
be returned with proper error_fun callback in chain_end
.
success_logical(data, ...) success_continue(data, ...) success_append(data, ...) success_report(data, ...) success_df_return(data, ...) error_stop(errors, data = NULL, warn = FALSE, ...) just_warn(errors, data = NULL) error_report(errors, data = NULL, warn = FALSE, ...) warn_report(errors, data = NULL) error_append(errors, data = NULL) warning_append(errors, data = NULL) error_return(errors, data = NULL) error_df_return(errors, data = NULL) error_logical(errors, data = NULL, ...) defect_append(errors, data, ...) defect_report(errors, data, ...) defect_df_return(errors, data, ...)
success_logical(data, ...) success_continue(data, ...) success_append(data, ...) success_report(data, ...) success_df_return(data, ...) error_stop(errors, data = NULL, warn = FALSE, ...) just_warn(errors, data = NULL) error_report(errors, data = NULL, warn = FALSE, ...) warn_report(errors, data = NULL) error_append(errors, data = NULL) warning_append(errors, data = NULL) error_return(errors, data = NULL) error_df_return(errors, data = NULL) error_logical(errors, data = NULL, ...) defect_append(errors, data, ...) defect_report(errors, data, ...) defect_df_return(errors, data, ...)
data 
A data frame 
... 
Further arguments passed to or from other methods 
errors 
A list of objects of class 
warn 
If TRUE, assertr will issue a warning instead of an error 
'summary' method for class "assertr_assert_error" This prints the error message and the first five rows of the twocolumn 'data.frame' holding the indexes and values of the offending data.
## S3 method for class 'assertr_assert_error' summary(object, ...)
## S3 method for class 'assertr_assert_error' summary(object, ...)
object 
An assertr_assert_error object 
... 
Additional arguments affecting the summary produced 
'summary' method for class "assertr_verify_error"
## S3 method for class 'assertr_verify_error' summary(object, ...)
## S3 method for class 'assertr_verify_error' summary(object, ...)
object 
An assertr_verify_error object 
... 
Additional arguments affecting the summary produced 
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
verify( data, expr, success_fun = success_continue, error_fun = error_stop, skip_chain_opts = FALSE, obligatory = FALSE, defect_fun = defect_append, description = NA )
verify( data, expr, success_fun = success_continue, error_fun = error_stop, skip_chain_opts = FALSE, obligatory = FALSE, defect_fun = defect_append, description = NA )
data 
A data frame, list, or environment 
expr 
A logical expression 
success_fun 
Function to call if assertion passes. Defaults to
returning 
error_fun 
Function to call if assertion fails. Defaults to printing a summary of all errors. 
skip_chain_opts 
If TRUE, 
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 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. 
For examples of possible choices for the success_fun
and
error_fun
parameters, run help("success_and_error_functions")
By default, the data
is returned if predicate assertion
is TRUE and and error is thrown if not. If a nondefault
success_fun
or error_fun
is used, the return
values of these function will be returned.
See vignette("assertr")
for how to use this in context
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)
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)
This function returns a predicate function that will take a numeric value
or vector and return TRUE if the value(s) is/are within the bounds set.
This does not actually check the bounds of anything–it only returns
a function that actually does the checking when called with a number.
This is a convenience function meant to return a predicate function to
be used in an assertr
assertion.
within_bounds( lower.bound, upper.bound, include.lower = TRUE, include.upper = TRUE, allow.na = TRUE, check.class = TRUE )
within_bounds( lower.bound, upper.bound, include.lower = TRUE, include.upper = TRUE, allow.na = TRUE, check.class = TRUE )
lower.bound 
The lowest permitted value 
upper.bound 
The upper permitted value 
include.lower 
A logical indicating whether lower bound should be inclusive (default TRUE) 
include.upper 
A logical indicating whether upprt bound should be inclusive (default TRUE) 
allow.na 
A logical indicating whether NAs (including NaNs) should be permitted (default TRUE) 
check.class 
Should the class of the 
A function that takes numeric value or numeric vactor and returns
TRUE if the value(s) is/are within the bounds defined by the
arguments supplied by within_bounds
and FALSE
otherwise
predicate < within_bounds(3,4) predicate(pi) ## is equivalent to within_bounds(3,4)(pi) # a correlation coefficient must always be between 0 and 1 coeff < cor.test(c(1,2,3), c(.5, 2.4, 4))[["estimate"]] within_bounds(0,1)(coeff) ## check for positive number positivep < within_bounds(0, Inf, include.lower=FALSE) ## this is meant to be used as a predicate in an assert statement assert(mtcars, within_bounds(4,8), cyl) ## or in a pipeline library(magrittr) mtcars %>% assert(within_bounds(4,8), cyl)
predicate < within_bounds(3,4) predicate(pi) ## is equivalent to within_bounds(3,4)(pi) # a correlation coefficient must always be between 0 and 1 coeff < cor.test(c(1,2,3), c(.5, 2.4, 4))[["estimate"]] within_bounds(0,1)(coeff) ## check for positive number positivep < within_bounds(0, Inf, include.lower=FALSE) ## this is meant to be used as a predicate in an assert statement assert(mtcars, within_bounds(4,8), cyl) ## or in a pipeline library(magrittr) mtcars %>% assert(within_bounds(4,8), cyl)
This function takes one argument, the number of median absolute
deviations within which to accept a particular data point. This is
generally more useful than its sister function within_n_sds
because it is more robust to the presence of outliers. It is therefore
better suited to identify potentially erroneous data points.
within_n_mads(n, ...)
within_n_mads(n, ...)
n 
The number of median absolute deviations from the median within which to accept a datum 
... 
Additional arguments to be passed to 
As an example, if '2' is passed into this function, this will return
a function that takes a vector and figures out the bounds of two
median absolute deviations (MADs) from the median. That function will then
return a within_bounds
function that can then be applied
to a single datum. If the datum is within two MADs of the median of the
vector given to the function returned by this function, it will return TRUE.
If not, FALSE.
This function isn't meant to be used on its own, although it can. Rather,
this function is meant to be used with the insist
function to
search for potentially erroneous data points in a data set.
A function that takes a vector and returns a
within_bounds
predicate based on the MAD
of that vector.
test.vector < rnorm(100, mean=100, sd=20) within.one.mad < within_n_mads(1) custom.bounds.checker < within.one.mad(test.vector) custom.bounds.checker(105) # returns TRUE custom.bounds.checker(40) # returns FALSE # same as within_n_mads(1)(test.vector)(40) # returns FALSE within_n_mads(2)(test.vector)(as.numeric(NA)) # returns TRUE # because, by default, within_bounds() will accept # NA values. If we want to reject NAs, we have to # provide extra arguments to this function within_n_mads(2, allow.na=FALSE)(test.vector)(as.numeric(NA)) # returns FALSE # or in a pipeline, like this was meant for library(magrittr) iris %>% insist(within_n_mads(5), Sepal.Length)
test.vector < rnorm(100, mean=100, sd=20) within.one.mad < within_n_mads(1) custom.bounds.checker < within.one.mad(test.vector) custom.bounds.checker(105) # returns TRUE custom.bounds.checker(40) # returns FALSE # same as within_n_mads(1)(test.vector)(40) # returns FALSE within_n_mads(2)(test.vector)(as.numeric(NA)) # returns TRUE # because, by default, within_bounds() will accept # NA values. If we want to reject NAs, we have to # provide extra arguments to this function within_n_mads(2, allow.na=FALSE)(test.vector)(as.numeric(NA)) # returns FALSE # or in a pipeline, like this was meant for library(magrittr) iris %>% insist(within_n_mads(5), Sepal.Length)
This function takes one argument, the number of standard deviations within which to accept a particular data point.
within_n_sds(n, ...)
within_n_sds(n, ...)
n 
The number of standard deviations from the mean within which to accept a datum 
... 
Additional arguments to be passed to 
As an example, if '2' is passed into this function, this will return
a function that takes a vector and figures out the bounds of two
standard deviations from the mean. That function will then return
a within_bounds
function that can then be applied
to a single datum. If the datum is within two standard deviations of
the mean of the vector given to the function returned by this function,
it will return TRUE. If not, FALSE.
This function isn't meant to be used on its own, although it can. Rather,
this function is meant to be used with the insist
function to
search for potentially erroneous data points in a data set.
A function that takes a vector and returns a
within_bounds
predicate based on the standard deviation
of that vector.
test.vector < rnorm(100, mean=100, sd=20) within.one.sd < within_n_sds(1) custom.bounds.checker < within.one.sd(test.vector) custom.bounds.checker(105) # returns TRUE custom.bounds.checker(40) # returns FALSE # same as within_n_sds(1)(test.vector)(40) # returns FALSE within_n_sds(2)(test.vector)(as.numeric(NA)) # returns TRUE # because, by default, within_bounds() will accept # NA values. If we want to reject NAs, we have to # provide extra arguments to this function within_n_sds(2, allow.na=FALSE)(test.vector)(as.numeric(NA)) # returns FALSE # or in a pipeline, like this was meant for library(magrittr) iris %>% insist(within_n_sds(5), Sepal.Length)
test.vector < rnorm(100, mean=100, sd=20) within.one.sd < within_n_sds(1) custom.bounds.checker < within.one.sd(test.vector) custom.bounds.checker(105) # returns TRUE custom.bounds.checker(40) # returns FALSE # same as within_n_sds(1)(test.vector)(40) # returns FALSE within_n_sds(2)(test.vector)(as.numeric(NA)) # returns TRUE # because, by default, within_bounds() will accept # NA values. If we want to reject NAs, we have to # provide extra arguments to this function within_n_sds(2, allow.na=FALSE)(test.vector)(as.numeric(NA)) # returns FALSE # or in a pipeline, like this was meant for library(magrittr) iris %>% insist(within_n_sds(5), Sepal.Length)