Creates a single data rule

Usage

rule(expr, name = NA, allow_na = FALSE, negate = FALSE, ...)

# S3 method for rule
print(x, ...)

Arguments

expr: an expression which dictates which determines when a rule is good. Note that the expression is evaluated in check_data(), within the given framework. That means, for example if a the data given to check_data() is an arrow dataset, the expression must be mappable from arrow (see also arrow documentation). The expression can be given as a string as well.
name: an optional name for the rule for reference
allow_na: does the rule allow for NA values in the data? default value is FALSE. Note that when NAs are introduced in the expression, allow_na has no effect. Eg when the rule as.numeric(vs) %in% c(0, 1) finds the values of vs as c("1", "A"), the rule will throw a fail regardless of the value of allow_na as the NA is introduced in the expression and is not found in the original data. However, when the values of vs are c("1", NA), allow_na will have an effect.
negate: is the rule negated, only applies to the expression not allow_na, that is, if expr = mpg > 10, allow_na = TRUE, and negate = TRUE, it would match all mpg <= 10 as well as NAs.
...: additional arguments that are carried along for your documentation, but are not used. Could be for example date, person, contact, comment, etc
x: a rule to print

Value

The rule values as a list

Methods (by generic)

print(rule): Prints a rule

Examples

r <- rule(mpg > 10)
r
#> <Verification Rule>
#>   expr: 'mpg > 10'
#>   name: 'Rule for: mpg'
#>   allow NA: FALSE
#>   negated:  FALSE

r2 <- rule(mpg > 10, name = "check that mpg is reasonable", allow_na = TRUE,
           negate = FALSE, author = "me", date = Sys.Date())
r2
#> <Verification Rule>
#>   expr: 'mpg > 10'
#>   name: 'check that mpg is reasonable'
#>   allow NA: TRUE
#>   negated:  FALSE
#>   author: 'me'
#>   date: '2024-01-10'

check_data(mtcars, r)
#>             name     expr allow_na negate tests pass fail warn error
#> 1: Rule for: mpg mpg > 10    FALSE  FALSE    32   32    0           
#>                 time
#> 1: 0.0003154278 secs

rs <- ruleset(
  rule(mpg > 10),
  rule(cyl %in% c(4, 6)), # missing 8
  rule(qsec >= 14.5 & qsec <= 22.9)
)
rs
#> <Verification Ruleset with 3 elements>
#>   [1] 'Rule for: mpg' matching `mpg > 10` (allow_na: FALSE)
#>   [2] 'Rule for: cyl' matching `cyl %in% c(4, 6)` (allow_na: FALSE)
#>   [3] 'Rule for: qsec' matching `qsec >= 14.5 & qsec <= 22.9` (allow_na: FALSE)
check_data(mtcars, rs)
#>              name                        expr allow_na negate tests pass fail
#> 1:  Rule for: mpg                    mpg > 10    FALSE  FALSE    32   32    0
#> 2:  Rule for: cyl            cyl %in% c(4, 6)    FALSE  FALSE    32   18   14
#> 3: Rule for: qsec qsec >= 14.5 & qsec <= 22.9    FALSE  FALSE    32   32    0
#>    warn error              time
#> 1:            0.0002570152 secs
#> 2:            0.0010795593 secs
#> 3:            0.0002388954 secs