approxExtrap {Hmisc} | R Documentation

## Linear Extrapolation

### Description

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.

### Usage

    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 `NA`s 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(s)

Frank Harrell

### See Also

`approx`

### Examples

    approxExtrap(1:3,1:3,xout=c(0,4))

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