[R] Dataframe modification
Gabor Grothendieck
ggrothendieck at gmail.com
Mon Aug 21 20:31:04 CEST 2006
Here are two solutions:
A <- 1:8
B <- c(1,2,4,7,8)
C <- c(5,3,10,12,17)
# solution 1 - assignment with subscripting
DF <- data.frame(A, B = A, C = 0)
DF[A %in% B, "C"] <- C
# solution 2 - merge
DF <- with(merge(data.frame(A), data.frame(B, C), by = 1, all = TRUE),
data.frame(A, B = A, C = ifelse(is.na(C), 0, C)))
On 8/21/06, Sachin J <sachinj.2006 at yahoo.com> wrote:
> Hi,
>
> How can I accomplish this in R.
>
> I have a Dataframe with 3 columns. Column B and C have same elements. But column A has more elements than B and C. I want to compare Column A with B and do the following:
>
> If A is not in B then insert a new row in B and C and fill these new rows with
> B = A and C = 0. So finally I will have balanced dataframe with equal no of rows (entries) in all the columns.
>
> For example:
>
> A[3] = 3 but is not in B. So insert new row and set B[3] = 3 (new row) and C[3] = 0. Final result would look like:
>
> A B C
> 1 1 5
> 2 2 3
> 3 3 0
> 4 4 10
> 5 5 0
> 6 6 0
> 7 7 12
> 8 8 17
>
> These are the columns of DF
> > a <- c(1,2,3,4,5,6,7,8)
> > b <- c(1,2,4,7,8)
> > c(5,3,10,12,17)
>
> Thanx in advance for the help.
>
> Sachin
>
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