R: Check whether a variable represents a linear sequence

is_linear_sequence {validate}

R Documentation

Check whether a variable represents a linear sequence

Description

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

Usage

is_linear_sequence(x, by = NULL, ...)

## S3 method for class 'numeric'
is_linear_sequence(
  x,
  by = NULL,
  begin = NULL,
  end = NULL,
  sort = TRUE,
  tol = 1e-08,
  ...
)

## S3 method for class 'Date'
is_linear_sequence(x, by = NULL, begin = NULL, end = NULL, sort = TRUE, ...)

## S3 method for class 'POSIXct'
is_linear_sequence(
  x,
  by = NULL,
  begin = NULL,
  end = NULL,
  sort = TRUE,
  tol = 1e-06,
  ...
)

## S3 method for class 'character'
is_linear_sequence(
  x,
  by = NULL,
  begin = NULL,
  end = NULL,
  sort = TRUE,
  format = "auto",
  ...
)

in_linear_sequence(x, ...)

## S3 method for class 'character'
in_linear_sequence(
  x,
  by = NULL,
  begin = NULL,
  end = NULL,
  sort = TRUE,
  format = "auto",
  ...
)

## S3 method for class 'numeric'
in_linear_sequence(
  x,
  by = NULL,
  begin = NULL,
  end = NULL,
  sort = TRUE,
  tol = 1e-08,
  ...
)

## S3 method for class 'Date'
in_linear_sequence(x, by = NULL, begin = NULL, end = NULL, sort = TRUE, ...)

## S3 method for class 'POSIXct'
in_linear_sequence(
  x,
  by = NULL,
  begin = NULL,
  end = NULL,
  sort = TRUE,
  tol = 1e-06,
  ...
)

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 ≤q 2 is a linear sequence.

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.

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) )

[Package validate version 1.0.2 Index]