Get or set the names of a vector

Source: R/names.R

These functions work like rlang::names2(), names() and names<-(), except that they return or modify the the rowwise names of the vector. These are:

  • The usual names() for atomic vectors and lists

  • The row names for data frames and matrices

  • The names of the first dimension for arrays Rowwise names are size consistent: the length of the names always equals vec_size().

vec_names2() returns the repaired names from a vector, even if it is unnamed. See vec_as_names() for details on name repair.

vec_names() is a bare-bones version that returns NULL if the vector is unnamed.

vec_set_names() sets the names or removes them.

vec_names2(
  x,
  ...,
  repair = c("minimal", "unique", "universal", "check_unique"),
  quiet = FALSE
)

vec_names(x)

vec_set_names(x, names)

Arguments

x

A vector with names
...

These dots are for future extensions and must be empty.
repair

Either a string or a function. If a string, it must be one of "check_unique", "minimal", "unique", or "universal". If a function, it is invoked with a vector of minimal names and must return minimal names, otherwise an error is thrown.

  • Minimal names are never NULL or NA. When an element doesn't have a name, its minimal name is an empty string.

  • Unique names are unique. A suffix is appended to duplicate names to make them unique.

  • Universal names are unique and syntactic, meaning that you can safely use the names as variables without causing a syntax error.

The "check_unique" option doesn't perform any name repair. Instead, an error is raised if the names don't suit the "unique" criteria.
quiet

By default, the user is informed of any renaming caused by repairing the names. This only concerns unique and universal repairing. Set quiet to TRUE to silence the messages.
names

A character vector, or NULL.

Value

vec_names2() returns the names of x, repaired. vec_names() returns the names of x or NULL if unnamed. vec_set_names() returns x with names updated.

Examples

vec_names2(1:3)

#> [1] "" "" ""
vec_names2(1:3, repair = "unique")

#> New names:
#> * `` -> ...1
#> * `` -> ...2
#> * `` -> ...3
#> [1] "...1" "...2" "...3"
vec_names2(c(a = 1, b = 2))

#> [1] "a" "b"

# `vec_names()` consistently returns the rowwise names of data frames and arrays:
vec_names(data.frame(a = 1, b = 2))

#> NULL
names(data.frame(a = 1, b = 2))

#> [1] "a" "b"
vec_names(mtcars)

#>  [1] "Mazda RX4"           "Mazda RX4 Wag"       "Datsun 710"         
#>  [4] "Hornet 4 Drive"      "Hornet Sportabout"   "Valiant"            
#>  [7] "Duster 360"          "Merc 240D"           "Merc 230"           
#> [10] "Merc 280"            "Merc 280C"           "Merc 450SE"         
#> [13] "Merc 450SL"          "Merc 450SLC"         "Cadillac Fleetwood" 
#> [16] "Lincoln Continental" "Chrysler Imperial"   "Fiat 128"           
#> [19] "Honda Civic"         "Toyota Corolla"      "Toyota Corona"      
#> [22] "Dodge Challenger"    "AMC Javelin"         "Camaro Z28"         
#> [25] "Pontiac Firebird"    "Fiat X1-9"           "Porsche 914-2"      
#> [28] "Lotus Europa"        "Ford Pantera L"      "Ferrari Dino"       
#> [31] "Maserati Bora"       "Volvo 142E"         
names(mtcars)

#>  [1] "mpg"  "cyl"  "disp" "hp"   "drat" "wt"   "qsec" "vs"   "am"   "gear"
#> [11] "carb"
vec_names(Titanic)

#> [1] "1st"  "2nd"  "3rd"  "Crew"
names(Titanic)

#> NULL

vec_set_names(1:3, letters[1:3])

#> a b c 
#> 1 2 3 
vec_set_names(data.frame(a = 1:3), letters[1:3])

#>   a
#> a 1
#> b 2
#> c 3