Hello -
Jia Ying Mei wrote:
Hi,
I know this can be done in Stata (which is quite messy) but I wanted to
know if it can be done in R. So lets say I have a merged data set (I
used the merge function by date for the attached two files), where all
the missing values are filled with NAs (which is what the all.x=TRUE does).
Is there any way to replace those NAs with the value of the latest row
that contains a value?
For example:
> Date<-read.table("Desktop/R/Testdate.txt", head=T, sep="\t")
> Data<-read.table("Desktop/R/Testinput.txt", head=T, sep="\t")
> Merged<-merge(Date, Data, all.x=TRUE)
> Merged
Date France Germany
1 3/10/07 2 4
2 3/11/07 NA NA
3 3/12/07 NA NA
4 3/13/07 NA NA
5 3/14/07 NA NA
6 3/15/07 1 2
Given this Merged data, is there a way to replace every NA value from
3/11 to 3/14 with that of 3/15? But then say there are multiple
intervals with NAs that I want to fill with the last given value?
Yes, no loop necessary.
# begin R code
install.packages("zoo")
library(zoo)
Merged$France <- na.locf(Merged$France, fromLast = TRUE)
# end R code
This will of course work on the 'France' column. Use of lapply in
conjuction with this idea will lead to solving this problem for N
columns in a couple lines of R. Not messy at all!
Best Regards,
Erik Iverson
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