tis: interpNA – R documentation

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tis

interpNA

Interpolate missing values in a Time Indexed Series

Description

Calls approxfun or splinefun to interpolate missing values in a tis object.

Usage

interpNA(x, method = "constant", useTimes = F, offset = 1, rule = 2, f = 0, ...)

Arguments

`x`	a `tis` time series
`method`	One of c("constant", "linear", "fmm", "natural", "periodic"). Methods "constant" and "linear" call `approxfun`; the others call `splinefun`.
`useTimes`	if `TRUE`, use `time(x, offset)` (the decimal times of `x`) as the 'x' part of the (x, y) pairs used for interpolation. If `FALSE` (the default), use `ti(x)` (the integer time indices of `x`) as the 'x' part of the (x, y) pairs.
`offset`	if `useTimes` is `TRUE`, a number in the range [0,1] telling where in the periods represented by `ti(x)` to get the points for the 'x' parts of the (x, y) pairs. See the help for `jul` for a more detailed explanation of this parameter.
`rule`	For methods "constant" and "linear": an integer describing how interpolation is to take place outside the interval [`min(x)`, `max(x)`]. If `rule` is `1` then `NA`s are returned for such points and if it is `2`, the value at the closest data extreme is used.
`f`	For `method="constant"` a number between 0 and 1 inclusive, indicating a compromise between left- and right-continuous step functions. If `y0` and `y1` are the values to the left and right of the point then the value is `y0(1-f)+y1f` so that `f=0` is right-continuous and `f=1` is left-continuous.
`...`	Other arguments passed along to `approxfun` for methods "constant" and "linear".

Details

Depending on the method specified, a call to either approxfun or splinefun is constructed with appropriate arguments and executed for each column of x. In the call to approxfun or splinefun, the time indices ti(x) (or the decimal times returned by time(x, offset), if useTimes is TRUE) serve as the 'x' argument and the column values as the 'y' argument.

Value

A tis object like x with NA values filled in by interpolated values.