IfElse: Conditional Data Selection

Description

This is equivalent to {if(test) yes else no}. The advantages of using this function are 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) yes else if(test2) u else v} (where arguments are given by name, not position).

Usage

IfElse(test, yes, no, ...)

Arguments

test

logical value; if TRUE return yes.

yes

any object; this is returned if test is TRUE.

normally any object; this is returned if test is FALSE. If there are more than three arguments this should be logical.

...

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 yes or no. With k arguments, one of arguments 2, 4, ..., k-1, k.

Details

test should be a scalar logical, and only one of yes or no is evaluated, depending on whether test = TRUE or test = FALSE, and yes and no may be any objects. In contrast, for ifelse, test is normally a vector, both yes and no are evaluated, even if not used, and yes and no are vectors the same length as test.

Examples

Run this code

# NOT RUN {
IfElse(TRUE, "cat", "dog")
IfElse(FALSE, "one", TRUE, "two", "three")
IfElse(FALSE, "one", FALSE, "two", "three")
# }