[R] Merging a dataframe after subsetting with respect to several factors

[Bert Gunter]

Why? I suspect that there is no reason that you need to do this.

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 Thu, Jun 13, 2019 at 1:22 PM Tina Chatterjee <tinamunim2019 using gmail.com>
wrote:

> Hello everyone!
> I have the following dataframe(df).
>
> a<-c("a1","a2","a2","a1","a1","a1")
> b<-c("b1","b1","b1","b1","b1","b2")
> c<-c("c1","c1","c1","c1","c1","c2")
> time <- c(runif(6,0,1))
>
> df<-data.frame(a,b,c,time)
> df
>
>    a  b  c       time
> 1 a1 b1 c1 0.28781082
> 2 a2 b1 c1 0.02102591
> 3 a2 b1 c1 0.72479220
> 4 a1 b1 c1 0.41947675
> 5 a1 b1 c1 0.58899855
> 6 a1 b2 c2 0.82414123
>
> Now, I want to extract the time components corresponding
> to the specific combination of the factors. Finally I have made a dataframe
> (df_1) with 2 columns one with the time components and the other with the
> level combinations.
>
> df[df$a=="a1" & df$b=="b1" & df$c=="c1",]$time
> df[df$a=="a2" & df$b=="b1" & df$c=="c1",]$time
> df[df$a=="a1" & df$b=="b2" & df$c=="c2",]$time
>
> val <- c(df[df$a=="a1" & df$b=="b1" & df$c=="c1",]$time,df[df$a=="a2" &
> df$b=="b1" & df$c=="c1",]$time,df[df$a=="a1" & df$b=="b2" &
> df$c=="c2",]$time)
> name <- c(rep("a1b1c1",3),rep("a2b1c1",2),"a1b2c2")
> df_1 <- data.frame(val,name)
>
> I made it manually. In reality I have a lot of treatment combinations. So,
> could you please suggest how can I do this with a loop or any control
> sequence?
> Thanks and regards.
> Tina
>
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>
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