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Attribute checks - Check for and filter attributes from object

attributes-filter.Rd

Functions to test for and filter attributes from an object. Attributes can be selected by abbreviation in abbr, by name in exact or disallow, or by regex pattern in match.

To remove attributes:

  • attrs_rmv() returns x without the attributes selected.

  • attrs_keep() returns x with only the attributes selected.

To test for attributes:

  • has_attrs_any() returns TRUE if any of the selected attributes are present.

  • has_attrs_all() returns TRUE if all of the selected attributes are present.

  • has_attrs_only() returns TRUE if all and only the selected attributes are present.

Usage

attrs_rmv(x, abbr = "", exact = character(), match = character(), perl = FALSE)

attrs_keep(
  x,
  abbr = "",
  exact = character(),
  match = character(),
  perl = FALSE
)

has_attrs_any(
  x,
  abbr = "",
  exact = character(),
  match = character(),
  disallow = character()
)

has_attrs_all(x, abbr = "", exact = character(), disallow = character())

has_attrs_only(x, abbr = "", exact = character())

Arguments

x

[any] Object to test for or remove attributes from.

abbr

[character(1)] String of characters specifying attributes to keep: "n" for 'names'; "d" for 'dim'; "c" for 'class'; "r" for both rownames and dimnames.

exact

[character()] Other attributes to keep, specified by name.

match

[character()] Other attributes to keep, specified by regex pattern. They are combined with the or regex 'or' operator |.

perl

[TRUE | FALSE] Whether to use perl-compatible regex.

disallow

[character()] Attributes that, if present, will fail the test.

Value

  • [=x] For attrs_rmv() and attrs_keep(): Same object as x but with attributes some removed.

  • [TRUE | FALSE] For has_attrs_any(), has_attrs_all(), and has_attrs_only(): the scalar result of the test.

Examples

x <- structure(
  1:3, a = 1, b = 2, c = 3,
  names = c("X", "Y", "Z"), dim = c(1, 3), class = "myclass",
  levels = c("aa", "bb", "cc")
)

# Default removal:
attrs_keep(x) # Removes all attributes
#> [1] 1 2 3
attrs_rmv(x) # Removes no attributes
#>      [,1] [,2] [,3]
#> [1,]    1    2    3
#> attr(,"a")
#> [1] 1
#> attr(,"b")
#> [1] 2
#> attr(,"c")
#> [1] 3
#> attr(,"names")
#> [1] "X" "Y" "Z"
#> attr(,"class")
#> [1] "myclass"
#> attr(,"levels")
#> [1] "aa" "bb" "cc"

# Abbreviation, exact, and regex filtering:
attrs_keep(x, abbr = "ncd") # Keeps names, dim, and class
#>      [,1] [,2] [,3]
#> [1,]    1    2    3
#> attr(,"names")
#> [1] "X" "Y" "Z"
#> attr(,"class")
#> [1] "myclass"
attrs_rmv(x, exact = c("levels", "b")) # Removes levels and b
#>      [,1] [,2] [,3]
#> [1,]    1    2    3
#> attr(,"a")
#> [1] 1
#> attr(,"c")
#> [1] 3
#> attr(,"names")
#> [1] "X" "Y" "Z"
#> attr(,"class")
#> [1] "myclass"
attrs_keep(x, match = "^[a-c]$") # Keeps only a, b, and c
#> [1] 1 2 3
#> attr(,"a")
#> [1] 1
#> attr(,"b")
#> [1] 2
#> attr(,"c")
#> [1] 3

# Testing for attributes:
has_attrs_any(x, "c", exact = "levels") #> TRUE (has class and levels)
#> [1] TRUE
has_attrs_any(x, "c", exact = "levels", disallow = "dim") #> FALSE (has dim)
#> [1] FALSE
has_attrs_all(x, exact = c("a", "b", "c")) #> TRUE
#> [1] TRUE
has_attrs_all(x, exact = c("a", "b", "c", "d")) #> FALSE (missing d)
#> [1] FALSE

has_attrs_only(x, exact = c("a", "b", "c")) #> FALSE (has other attributes)
#> [1] FALSE