Ensure the ‘Truth’ of R Expressions

Description

If any of the expressions in ... are not all TRUE, stop is called, producing an error message indicating the first element of ... which was not true.

Usage

stopifnot(...)

Arguments

Details

stopifnot(A, B) is conceptually equivalent to { if(!all(A)) stop(...) ; if(!all(B)) stop(...) }.

Value

(NULL if all statements in ... are TRUE.)

See Also

stop, warning.

Examples

stopifnot(1 == 1, all.equal(pi, 3.14159265), 1 < 2) # all TRUE

m <- matrix(c(1,3,3,1), 2,2)
stopifnot(m == t(m), diag(m) == rep(1,2)) # all(.) |=>  TRUE

options(error = expression(NULL))# "disable stop(.)"  << Use with CARE! >>

stopifnot(all.equal(pi, 3.141593),  2 < 2, all(1:10 < 12), "a" < "b")
stopifnot(all.equal(pi, 3.1415927), 2 < 2, all(1:10 < 12), "a" < "b")

options(error = NULL)# revert to default error handler