validate (version 1.1.5)

is_linear_sequence: Check whether a variable represents a linear sequence

Description

A variable \(X = (x_1, x_2,\ldots, x_n)\) (\(n\geq 0\)) represents a linear sequence when \(x_{j+1} - x_j\) is constant for all \(j\geq 1\). That is, elements in the series are equidistant and without gaps.

Usage

is_linear_sequence(x, by = NULL, ...)
# S3 method for numeric
is_linear_sequence(
  x,
  by = NULL,
  begin = NULL,
  end = NULL,
  sort = TRUE,
  tol = 1e-08,
  ...
)
# S3 method for Date
is_linear_sequence(x, by = NULL, begin = NULL, end = NULL, sort = TRUE, ...)
# S3 method for POSIXct
is_linear_sequence(
  x,
  by = NULL,
  begin = NULL,
  end = NULL,
  sort = TRUE,
  tol = 1e-06,
  ...
)
# S3 method for character
is_linear_sequence(
  x,
  by = NULL,
  begin = NULL,
  end = NULL,
  sort = TRUE,
  format = "auto",
  ...
)
in_linear_sequence(x, ...)
# S3 method for character
in_linear_sequence(
  x,
  by = NULL,
  begin = NULL,
  end = NULL,
  sort = TRUE,
  format = "auto",
  ...
)
# S3 method for numeric
in_linear_sequence(
  x,
  by = NULL,
  begin = NULL,
  end = NULL,
  sort = TRUE,
  tol = 1e-08,
  ...
)
# S3 method for Date
in_linear_sequence(x, by = NULL, begin = NULL, end = NULL, sort = TRUE, ...)
# S3 method for POSIXct
in_linear_sequence(
  x,
  by = NULL,
  begin = NULL,
  end = NULL,
  sort = TRUE,
  tol = 1e-06,
  ...
)

Value

For is_linear_sequence: a single TRUE or FALSE, equal to all(in_linear_sequence).

For in_linear_sequence: a logical vector with the same length as x.

Arguments

x

An R vector.

by

bare (unquoted) variable name or a list of unquoted variable names, used to split x into groups. The check is executed for each group.

...

Arguments passed to other methods.

begin

Optionally, a value that should equal min(x)

end

Optionally, a value that should equal max(x)

sort

[logical]. When set to TRUE, x is sorted within each group before testing.

tol

numerical tolerance for gaps.

format

[character]. How to interpret x as a time period. Either "auto" for automatic detection or a specification passed to strptime. Automatically detected periods are of the form year: "2020", yearMmonth: "2020M01", yearQquarter: "2020Q3", or year-Qquarter: "2020-Q3".

Details

Presence of a missing value (NA) in x will result in NA, except when length(x) <= 2 and start and end are NULL. Any sequence of length \(\leq 2\) is a linear sequence.

See Also

Other cross-record-helpers: contains_exactly(), do_by(), exists_any(), hb(), hierarchy(), is_complete(), is_unique()

Examples

is_linear_sequence(1:5) # TRUE
is_linear_sequence(c(1,3,5,4,2)) # FALSE
is_linear_sequence(c(1,3,5,4,2), sort=TRUE) # TRUE 
is_linear_sequence(NA_integer_) # TRUE
is_linear_sequence(NA_integer_, begin=4) # FALSE
is_linear_sequence(c(1, NA, 3)) # FALSE


d <- data.frame(
    number = c(pi, exp(1), 7)
  , date = as.Date(c("2015-12-17","2015-12-19","2015-12-21"))
  , time = as.POSIXct(c("2015-12-17","2015-12-19","2015-12-20"))
)

rules <- validator(
    is_linear_sequence(number)  # fails
  , is_linear_sequence(date)    # passes
  , is_linear_sequence(time)    # fails
)
summary(confront(d,rules))

## check groupwise data
dat <- data.frame(
   time = c(2012, 2013, 2012, 2013, 2015)
 , type = c("hi", "hi", "ha", "ha", "ha")
)
rule <- validator(in_linear_sequence(time, by=type))
values(confront(dat, rule)) ## 2xT, 3xF


rule <- validator(in_linear_sequence(time, type))
values( confront(dat, rule) )