Using logical functions

A logical vector only takes TRUE or FALSE and is mostly used to filter data. In practice, it is common to create joint conditions by multiple logical vectors where a number of logical operators and functions may involve.

Logical operators

Like many other programming languages, R enables a few operators to do basic logical calculations. The following table demonstrates what they do:

Symbol	Description	Example	Result
&	Vectorized AND	c(T, T) & c(T, F)	c(TRUE, FALSE)
|	Vectorized OR	c(T, T) | c(T, F)	c(TRUE, TRUE)
&&	Univariate AND	c(T, T) && c(F, T)	FALSE
||	Univariate OR	c(T, T) || c(F, T)	TRUE
!	Vectorized NOT	!c(T, F)	c(FALSE, TRUE)
%in%	Vectorized IN	c(1, 2) %in% c(1, 3, 4, 5)	c(TRUE, FALSE)

Note that in an if expression, && and || are often used to perform logical calculations that are only needed to yield a single-element logical vector. However, the potential risk of using && is that if it is made...