[R] Missing Values
murdoch at stats.uwo.ca
Mon Dec 6 16:36:25 CET 2004
On Mon, 6 Dec 2004 15:26:40 -0000 (GMT), nhy303 at abdn.ac.uk wrote :
>I have just started using R for my PhD. I am importing my data from Excel
>via notepad into Word. Unfortunately, my data has many missing values. I
>have put '.' and this allowed me to import the data into R. However, I
>now want to interpolate these missing values. Please can someone give me
>some pointers as to the method/code I could use?
The approx() function does linear interpolation.
> x <- 1:10
> y <- c(1, NA, 3, NA, NA, 2, NA, NA, NA, NA)
> approx(x, y, xout = x)
 1 2 3 4 5 6 7 8 9 10
 1.000000 2.000000 3.000000 2.666667 2.333333 2.000000 NA
 NA NA
To get it to extrapolate those values at the end, you could try "rule
= 2", but this might not do what you want...
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