[R] Fill in empty spaces modified

[William Dunlap]

The following, locf2(), does what you want using only base R functions:

locf2 <-
function(x, initial=NA, IS_BAD = is.na) {
    # Replace 'bad' values in 'x' with last previous non-bad value.
    # If no previous non-bad value, replace with 'initial'.
    stopifnot(is.function(IS_BAD))
    good <- !IS_BAD(x)
    stopifnot(is.logical(good), length(good) == length(x), !anyNA(good))
    i <- cumsum(good)
    x <- x[c(1,which(good))][i+1]
    x[i==0] <- initial
    x
}

In your example, you can use IS_BAD=function(x)x=="" or function(x)is.na(x)
| x==""

> df1 <- data.frame(nam=c("mandy","", "John","","","","Zara",""),
+                   val=c(1,2,3,4,5,6,7,8))
> cbind(df1, FilledNam = locf2(df1$nam, IS_BAD=function(x)x==""))
    nam val FilledNam
1 mandy   1     mandy
2         2     mandy
3  John   3      John
4         4      John
5         5      John
6         6      John
7  Zara   7      Zara
8         8      Zara
>




Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Wed, Aug 9, 2017 at 2:20 PM, Ek Esawi <esawiek at gmail.com> wrote:

> Hi All—
>
> I was looking at a posting from June-17. I managed to solve it. However,
> when I changed the example in the posting, my solution will work only once
> at a time which was mentioned by Jim Lemon  on his response to the original
> posting. This means that my solution will have to be repeated as many times
> as the maximum number of spaces on each gap; something that may not work
> well for large files.
>
> I am trying to solve the new example with base R functions only. I thought
> of splitting the first column to multiple lists and use one of the apply
> functions, but was not successful.
>
> Would apprecaite some hints on how to go about it.
>
> Thanks as always in advance—EK
>
> The posted data frame from the original posting:
> names val
> 1 Mandy   1
> 2         2
> 3 John    2
> 4         2
>
> My modified data frame:
> val <- c(1,2,3,4,5,6,7,8)
> nam <- c("mandy","", "John","","","","Zara","")
> df1 <- data.frame(nam,val)
>
>     nam val
> 1 mandy   1
> 2         2
> 3  John   3
> 4         4
> 5         5
> 6         6
> 7  Zara   7
> 8         8
>
> My code for solving the original data farme
> > which(df1$nam=="")
> > a <- which(df1$nam=="")
> > df1$nam[a] <- df1$nam[a-1]
>
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>
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