Number of Sign Changes in Sequence

Compute the number of sign changes in the sequence y.

nr.sign.chg(y)

Arguments

y

numeric vector.

Value

an integer giving the number of sign changes in sequence y. Note that going from positive to 0 to positive is not a sign change.

Author

Martin Maechler, 17 Feb 1993.

Examples

(y <- c(1:2,1:-1,0:-2))
#> [1]  1  2  1  0 -1  0 -1 -2
nr.sign.chg(y)## = 1
#> [1] 1