Conditional Data Selection
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).
ifelse1(test, x, y, ...)
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. |
test should be a scalar logical, and only one of x or
y is evaluated, depending on whether test = TRUE or
test = FALSE, and x and y may be any objects.
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.
with three arguments, one of x or y.
With k arguments, one of arguments 2, 4, ..., k-1, k.
ifelse1(TRUE, "cat", "dog") ifelse1(FALSE, "one", FALSE, "two", "three")
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