Extract values from predicate names

This function extracts the value part from a character vector of predicate names. Each element of x is expected to follow the pattern <varname>=<value>, where <varname> is a variable name and <value> is the associated value.

Usage

values(x)

Arguments

x: A character vector of predicate names.

Value

A character vector containing the <value> parts of predicate names in x. Elements without an equal sign return an empty string. If x is NULL, the function returns NULL. If x is an empty vector (character(0)), the function returns an empty vector (character(0)).

Details

If an element does not contain an equal sign (=), the function returns an empty string for that element.

This function is the counterpart to var_names(), which extracts the variable part of predicates. Together, var_names() and values() provide a convenient way to split predicate strings into their variable and value components.

Author

Michal Burda

Examples

values(c("a=1", "a=2", "b=x", "b=y"))
#> [1] "1" "2" "x" "y"
# returns c("1", "2", "x", "y")

values(c("a", "b=3"))
#> [1] ""  "3"
# returns c("", "3")