DATA MINING
Desktop Survival Guide by Graham Williams |
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Objects of type logical take on the values TRUE or
FALSE. The basic logical operators include:
! | Not | Less than | Less than or equal to | ||
Equal to | Greater than | Greater than or equal to | |||
& | And | | |
Or | && || |
Non vectorised versions |
> 5 == 4 # FALSE > 5 != 4 # TRUE > ! 1 - 1 # TRUE since 1-1 is 0 and is coerced to FALSE > TRUE * 2 # 2 since TRUE is coerced to 1. |
The single logical connectives &
and |
operates on vectors, whilst the double connective returns a single
result, and does a minimal amount of comparison to get the
result.
> c(TRUE, TRUE, FALSE) & c(TRUE, FALSE, FALSE) [1] TRUE FALSE FALSE > c(TRUE, TRUE, FALSE) && c(TRUE, FALSE, FALSE) [1] TRUE |