This is equivalent to {if(test) x else y} . The main
advantage of using this function is better formatting, and a more
natural syntax when the result is being assigned; see examples below.
With 5 arguments, this is equivalent to {if(test1) x else if(test2) u
else v} (where arguments are given by name, not position).
In ifelse1, is.numeric.atomic.vector, test should be a single value, and the calculations for y
(or x) are not performed if it is not selected. In contrast, for
ifelse, test is normally a vector, both x and y are evaluated, even if
not used, and x and y are vectors the same length as test.
Usage
ifelse1(test, x, y, ...)
Arguments
test
logical value; if TRUE return x.
x
any object; this is returned if test is TRUE.
y
any object; this is returned if test is FALSE.
...
there should be 3, 5, 7, etc. arguments to this function; arguments 1, 3, 5, etc. should be logical values; the other arguments (even numbered, and last) are objects that may be returned.
Value
with three arguments, one of x or y. With k arguments, one of arguments 2, 4, ..., k-1, k.