在R中，什么评估为True / False？

?logical

Details:

     ‘TRUE’ and ‘FALSE’ are reserved words denoting logical constants
     in the R language, whereas ‘T’ and ‘F’ are global variables whose
     initial values set to these.  All four are ‘logical(1)’ vectors.

     Logical vectors are coerced to integer vectors in contexts where a
     numerical value is required, with ‘TRUE’ being mapped to ‘1L’,
     ‘FALSE’ to ‘0L’ and ‘NA’ to ‘NA_integer_’.

5 == 1L

5 == 0L

FALSE

1 == 1L

0 == 0L

1 == TRUE

0 == FALSE

TRUE

FALSE

TRUE

TRUE

> isTRUE(TRUE)
[1] TRUE
> isTRUE(1)
[1] FALSE
> isTRUE(T)
[1] TRUE
> T <- 2
> isTRUE(T)
[1] FALSE

isTRUE

identical(x, TRUE)

?isTRUE

Details:
....

     ‘isTRUE(x)’ is an abbreviation of ‘identical(TRUE, x)’, and so is
     true if and only if ‘x’ is a length-one logical vector whose only
     element is ‘TRUE’ and which has no attributes (not even names).

FALSE

FALSE

> identical(F, FALSE)
[1] TRUE
> identical(0, FALSE)
[1] FALSE
> F <- \"hello\"
> identical(F, FALSE)
[1] FALSE

isTRUE()

identical(x, FALSE)

TRUE

FALSE

==

T

TRUE

F

FALSE

T

F

TRUE

FALSE

1 == TRUE

0 == FALSE

3 - 2 == TRUE