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Are objects named?

Source: R/are_attr.r
are_named.Rd

Wrappers around rlang predicates that allow multiple objects to be passed. The following documentation is adapted from the rlang documentation:

  • are_named() is a scalar predicate that checks that objects in ... have a names attribute and that none of the names are missing or empty (NA or "").

  • are_named2() is like are_named() but always returns TRUE for empty vectors, even those that don't have a names attribute. In other words, it tests for the property that each element of a vector is named. are_named2() composes well with names2() whereas are_named() composes with names().

  • have_names() is a vectorised variant.

Usage

are_named(..., .all = FALSE)

are_named2(..., .all = FALSE)

have_names(..., .all = FALSE)

Arguments

...

Objects to be tested.

.all

Whether to return if all arguments are TRUE.

Value

are_named() and are_named2() return a named logical, or unnamed boolean if .all is TRUE. have_names() is vectorised and returns a list of logical vectors whhere each is as long as the input object. When .all is TRUE for have_names(), all logical vectors are collapsed and a boolean is returned.

See also

are-bare-type-predicates rlang::is_named

Examples

# are_named() is a scalar predicate about the whole vector of names:
x <- c(a = 1, b = 2)
are_named(x, c(a = 1, 2))
#>           x c(a = 1, 2) 
#>        TRUE       FALSE 
are_named(x, c(a = 1, 2), .all = TRUE)
#> [1] FALSE

# Unlike are_named2(), are_named() returns `FALSE` for empty vectors
# that don't have a `names` attribute.
are_named(list(), vector())
#>   list() vector() 
#>    FALSE    FALSE 
are_named2(list(), vector())
#>   list() vector() 
#>     TRUE     TRUE 

# have_names() is vectorised
y <- c(a = 1, 2)
have_names(x, y, c(a = 1, 2, 3))
#> $x
#> [1] TRUE TRUE
#> 
#> $y
#> [1]  TRUE FALSE
#> 
#> $`c(a = 1, 2, 3)`
#> [1]  TRUE FALSE FALSE
#> 
have_names(x, y, c(a = 1, 2, 3), .all = TRUE)
#> [1] FALSE

# Empty and missing names are treated as invalid:
invalid <- setNames(letters[1:5], letters[1:5])
names(invalid)[1] <- ""
names(invalid)[3] <- NA

are_named(invalid)
#> invalid 
#>   FALSE 
have_names(invalid)
#> $invalid
#> [1] FALSE  TRUE FALSE  TRUE  TRUE
#> 

# A data frame normally has valid, unique names
# but a matrix usually doesn't because the names
# are stored in a different attribute.
mat <- matrix(1:4, 2)
colnames(mat) <- c("a", "b")
are_named(mtcars, mat)
#> mtcars    mat 
#>   TRUE  FALSE 
have_names(mtcars, mat)
#> $mtcars
#>  [1] TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
#> 
#> $mat
#> [1] FALSE FALSE FALSE FALSE
#>