Why do logical operators negate their argument when there is only one argument in R?

Question

160 views Asked by Mert Nuhoglu At 20 June 2015 at 08:03

When passing only a single vector to the logical and/or operator, the operator negates the argument:

> x = c(F,T,T)
> `&`(x)
[1]  TRUE FALSE FALSE

> `|`(x)
[1]  TRUE FALSE FALSE

To make the logical operator work as idempotent, one needs to pass a single element vector as the second argument:

> `&`(x,T)
[1] FALSE  TRUE  TRUE

> `|`(x,F)
[1] FALSE  TRUE  TRUE

Why do the logical operators negate their argument when there is only one argument passed?

There are 1 answers

**Thomas** · Accepted Answer · 2015-06-20 08:20:50

Thomas On 20 June 2015 at 08:20 BEST ANSWER

This was modified in R 3.2.1 as a result of a bug report. As you've pointed out, the previous behavior made little sense:

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