[R] Conditions

[Bert Gunter]

I generally find nested ifelse's to be confusing and prone to error, so I
usually prefer to proceed sequentially using subsetting with logicals or
replicated, but not nested ifelse's. In your example, the translation to
logical indexing seems pretty straightforward.

Using your example:

> dat2 <-within(dat2,
   {
      d4 <- d1 ## d1. 0 when d1 == 0
      d4[!d4]<- d2[!d4]
      d4[!d4]<- d3[!d4]
   })

> dat2
  ID d1 d2 d3 d4
1  A  0 25 35 25
2  B 12 22  0 12
3  C  0  0 31 31
4  E 10 20 30 10
5  F  0  0  0  0


Cheers,
Bert

Bert Gunter

"The trouble with having an open mind is that people keep coming along and
sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )


On Tue, Nov 26, 2019 at 3:15 PM Val <valkremk using gmail.com> wrote:

> HI All, I am having a little issue in my ifelse statement,
> The data frame looks like as follow.
>
> dat2 <-read.table(text="ID  d1 d2 d3
> A 0 25 35
> B 12 22  0
> C 0  0  31
> E 10 20 30
> F 0  0   0",header=TRUE,stringsAsFactors=F)
> I want to create d4 and set the value based on the following conditions.
> If d1  !=0  then d4=d1
> if d1 = 0  and d2 !=0  then d4=d2
> if (d1  and d2 = 0) and d3  !=0 then d4=d3
> if all d1, d2 and d3 =0 then d4=0
>
> Here is the desired output and my attempt
>  ID d1 d2 d3 d4
>   A  0 25 35  25
>   B 12 22  0  12
>   C  0  0 31   31
>   E 10 20 30  10
>   F  0  0  0  0  0
>
> My attempt
> dat2$d4 <-  0
> dat2$d4  <- ifelse((dat2$d1 =="0"), dat2$d2, ifelse(dat2$d2 == "0"),
> dat2$d3, 0)
> but not working.
>
> Thank you.
>
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