berryFunctions (version 1.22.5)

approx2: Smart linear NA interpolation

Description

Smart interpolation: as approx, approx2 fills NAs in a vector with linear interpolation, but unlike approx, it can handle NAs at the ends of a vector (takes the first/last value available for those). Also, approx2 returns a vector only.

Usage

approx2(x, fill = NULL, n = length(x), quiet = FALSE, ...)

Value

Vector with NAs replaced with interpolation (not a list, as in approx!)

Arguments

x

Vector with (numeric) values

fill

Function to fill NAs at the start or end of the vector. See Details. DEFAULT: NULL

n

Number of points to interpolate to

quiet

Logical: suppress warning for no non-NA values? DEFAULT: FALSE

...

Further arguments passed to approx

Author

Berry Boessenkool, , July 2015

Details

The function fill is used to fill missing values at the ends of the vector. It could be mean or median, for example, but must be a function that accepts na.rm=TRUE as an argument. The default (NULL) means to use the first (or last) observation available.

See Also

approx, zoo::na.locf, ciBand for usage example

Examples

approx2(c(NA,NA))   # yields a message
approx2(c(NA,NA, 6, 4, 8, 9, 3, 2, 1)) # fills with first non-NA value
approx2(c( 2,NA, 6, 4, 8, 9, 3, 2, 1)) # interpolates linearly
approx2(c( 2, 4, 6, 4, 8, 9,NA, 2,NA)) # linear, then last non-NA at end

approx2(c(NA,NA, 6, 4, 8, 9, 3, 2, 1))
approx2(c(NA,NA, 6, 4, 8, 9, 3, 2, 1), fill=median) # first median, then linear
approx2(c(NA,NA, 6, 4, 8, 9, 3, 2, 1), fill=mean)

approx2(c( 3, 4, 6, 4, 8, 9,NA, 2,NA))
approx2(c( 3, 4, 6, 4, 8, 9,NA, 2,NA), fill=median)
approx2(c( 3, 4, 6, 4, 8, 9,NA, 2,NA), fill=mean)

approx2(c(NA,NA, 6, 4, 8, 9, 3, 2, 1), n=17)
approx2(c( 2,NA, 6, 4, 8, 9, 3, 2, 1), n=17)
approx2(c( 2, 4, 6, 4, 8, 9,NA, 2,NA), n=17)