Dear Bert and Jeff,Sir,
I am a beginner in using R. I wanted a data frame because I need it for my
further calculations. So, could you please suggest how this can be done
using tapply() /filter() function?
Regards.
Tina
On Fri, Jun 14, 2019 at 7:30 AM Bert Gunter <bgunter.4...@gmail.com> wrote:
Jeff:
Your solution is not quite what she asked for (she wanted a data
frame, not a list).
Moreover, most of the time it is done automatically as the first step
of a tapply() /filter() type operation or is inherent in modeling and
trellis-type plots. I *still* suspect it is unnecessary, but of course
I could be wrong. That's why I asked for clarification.
Cheers,
Bert
On Thu, Jun 13, 2019 at 5:34 PM Jeff Newmiller
<jdnew...@dcn.davis.ca.us> wrote:
I do it regularly.
Base R:
result <- split( DF[ , 4, drop=FALSE ], DF[ , -4 ] )
Tidyverse:
library(tidyr)
result <- nest( DF, time )
filter( result, "a2"==a & "b1"==b & "c1"==c )[[ "data" ]]
On Thu, 13 Jun 2019, Bert Gunter wrote:
> 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
<tinamunim2...@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
>>
>> [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and
more, see
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>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained,
reproducible code.
>>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and
more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained,
reproducible code.
>
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