R Language The logical class Logical operators
Example
There are two sorts of logical operators: those that accept and return vectors of any length (elementwise operators: !, |, &, xor()) and those that only evaluate the first element in each argument (&&, ||). The second sort is primarily used as the cond argument to the if function.
| Logical Operator | Meaning | Syntax |
|---|---|---|
| ! | Not | !x |
| & | element-wise (vectorized) and | x & y |
| && | and (single element only) | x && y |
| | | element-wise (vectorized) or | x | y |
| || | or (single element only) | x || y |
| xor | element-wise (vectorized) exclusive OR | xor(x,y) |
Note that the || operator evaluates the left condition and if the left condition is TRUE the right side is never evaluated. This can save time if the first is the result of a complex operation. The && operator will likewise return FALSE without evaluation of the second argument when the first element of the first argument is FALSE.
> x <- 5
> x > 6 || stop("X is too small")
Error: X is too small
> x > 3 || stop("X is too small")
[1] TRUE
To check whether a value is a logical you can use the is.logical() function.
