Linear Extrapolation

Works in conjunction with the approx function to do linear extrapolation. approx in R does not support extrapolation at all, and it is buggy in S-Plus 6.

approxExtrap(x, y, xout, method = "linear", n = 50, rule = 2, f = 0,
             ties = "ordered", na.rm = FALSE)

Arguments

x,y,xout,method,n,rule,f

see approx

ties

applies only to R. See approx

na.rm

set to TRUE to remove NAs in x and y before proceeding

Details

Duplicates in x (and corresponding y elements) are removed before using approx.

Value

a vector the same length as xout

Author

Frank Harrell

See also

approx

Examples

approxExtrap(1:3,1:3,xout=c(0,4))
#> $x
#> [1] 0 4
#> 
#> $y
#> [1] 0 4
#>