The function assumes that x
is a vector of predicate names, i.e., a character
vector with elements compatible with pattern <varname>=<value>
. The function
returns the <varname>
part of these elements. If the string does not
correspond to the pattern <varname>=<value>
, i.e., if the equal sign (=
)
is missing in the string, the whole string is returned.
Examples
var_names(c("a=1", "a=2", "b=x", "b=y")) # returns c("a", "a", "b", "b")
#> [1] "a" "a" "b" "b"