Create vectors — vector-construction • rlang

The atomic vector constructors are equivalent to c() but:

They allow you to be more explicit about the output type. Implicit coercions (e.g. from integer to logical) follow the rules described in vector-coercion.
They use dynamic dots.

Usage

lgl(...)

int(...)

dbl(...)

cpl(...)

chr(...)

bytes(...)

Arguments

...: Components of the new vector. Bare lists and explicitly spliced lists are spliced.

Life cycle

All the abbreviated constructors such as lgl() will probably be moved to the vctrs package at some point. This is why they are marked as questioning.
Automatic splicing is soft-deprecated and will trigger a warning in a future version. Please splice explicitly with !!!.

Examples

# These constructors are like a typed version of c():
c(TRUE, FALSE)
#> [1]  TRUE FALSE
lgl(TRUE, FALSE)
#> [1]  TRUE FALSE

# They follow a restricted set of coercion rules:
int(TRUE, FALSE, 20)
#> [1]  1  0 20

# Lists can be spliced:
dbl(10, !!! list(1, 2L), TRUE)
#> [1] 10  1  2  1


# They splice names a bit differently than c(). The latter
# automatically composes inner and outer names:
c(a = c(A = 10), b = c(B = 20, C = 30))
#> a.A b.B b.C 
#>  10  20  30 

# On the other hand, rlang's constructors use the inner names and issue a
# warning to inform the user that the outer names are ignored:
dbl(a = c(A = 10), b = c(B = 20, C = 30))
#> Warning: Outer names are only allowed for unnamed scalar atomic inputs
#>  A  B  C 
#> 10 20 30 
dbl(a = c(1, 2))
#> Warning: Outer names are only allowed for unnamed scalar atomic inputs
#> [1] 1 2

# As an exception, it is allowed to provide an outer name when the
# inner vector is an unnamed scalar atomic:
dbl(a = 1)
#> a 
#> 1 

# Spliced lists behave the same way:
dbl(!!! list(a = 1))
#> a 
#> 1 
dbl(!!! list(a = c(A = 1)))
#> Warning: Outer names are only allowed for unnamed scalar atomic inputs
#> A 
#> 1 

# bytes() accepts integerish inputs
bytes(1:10)
#>  [1] 01 02 03 04 05 06 07 08 09 0a
bytes(0x01, 0xff, c(0x03, 0x05), list(10, 20, 30L))
#> [1] 01 ff 03 05 0a 14 1e