Coerce a list to keyvalue object

x should be a list with properties described in section "Details".

# S3 method for list
as.keyvalue(x, ...)

Arguments

x	a list with properties described in the details section.
...	further arguments passed to as.keyvalue.

Value

The function returns an object of class keyvalue (and list.

Details

• All names of the list elements should be unique.

• All elements of the list should be named.

• All keys should be unique (a key should only be mappad to one value).

• All elements of the list should be atomic vectors.

See also

as.keyvalue

Examples

ex <- list(
 fruit  = c("banana", "orange", "kiwi"),
 car    = c("SAAB", "Volvo", "taxi", "truck"),
 animal = c("elephant")
)
as.keyvalue(ex)
#>        key  value
#> 1   banana  fruit
#> 8 elephant animal
#> 3     kiwi  fruit
#> 2   orange  fruit
#> 4     SAAB    car
#> 6     taxi    car
#> 7    truck    car
#> 5    Volvo    car
is.keyvalue(ex)
#> [1] FALSE

# \donttest{
# An invalid list (non unique names; not because of silly classification)
ex2 <- list(
 fruit  = c("banana", "orange", "kiwi"),
 car    = c("SAAB", "Volvo", "taxi", "truck"),
 animal = c("elephant"),
 fruit  = c("President_Obama")
)
as.keyvalue(ex2)
#> Error in as.keyvalue.list(ex2): All list element names must be unique!

# An invalid list (non unique keys; kiwi appear twice)
ex3 <- list(
 fruit  = c("banana", "orange", "kiwi"),
 car    = c("SAAB", "Volvo", "taxi", "truck"),
 animal = c("elephant", "kiwi")
)
as.keyvalue(ex3)
#> Error in as.keyvalue.list(ex3): Some key(s) have duplicates! A key should only be mapped to one value (be found in one element of the list)
# }