[R] Grouping and/or splitting

[Berend Hasselman]

On 04-04-2012, at 07:15, Ashish Agarwal wrote:

> Yes. I was missing the DROP argument.
> But now the problem is splitting is causing some weird ordering of groups.

Why weird?

> See below:
> 
> DF <- read.table(text="
> Houseid,Personid,Tripid,taz
> 1,1,1,4
> 1,1,2,7
> 2,1,1,96
> 2,1,2,4
> 2,1,3,2
> 2,2,1,58
> 3,1,5,7
> ", header=TRUE, sep=",")
> aa <- split(DF, DF[, 1:2], drop=TRUE)
> 
> Now the result is aa[3] should is (3,1) and not (2,2). Why? How can I
> preserve the ascending order?
> 

Try this

aa[order(names(aa))]

Berend

>> aa[3]
> $`3.1`
>  Houseid Personid Tripid taz
> 7       3        1      5   7
>> aa[4]
> $`2.2`
>  Houseid Personid Tripid taz
> 6       2        2      1  58
> 
> 
> On Wed, Apr 4, 2012 at 6:29 AM, Rui Barradas <rui1174 at sapo.pt> wrote:
> 
>> Hello,
>> 
>> 
>> Ashish Agarwal wrote
>>> 
>>> I have a dataframe imported from csv file below:
>>> 
>>> Houseid,Personid,Tripid,taz
>>> 1,1,1,4
>>> 1,1,2,7
>>> 2,1,1,96
>>> 2,1,2,4
>>> 2,1,3,2
>>> 2,2,1,58
>>> 
>>> There are three groups identified based on the combination of first and
>>> second columns. How do I split this data frame?
>>> 
>>> I tried
>>> aa <- split(inpfil, inpfil[,1:2])
>>> but it has problems.
>>> 
>>> Output desired is
>>> 
>>> aa[1]
>>> Houseid,Personid,Tripid,taz
>>> 1,1,1,4
>>> 1,1,2,7
>>> aa[2]
>>> Houseid,Personid,Tripid,taz
>>> 2,1,1,96
>>> 2,1,2,4
>>> 2,1,3,2
>>> aa[3]
>>> Houseid,Personid,Tripid,taz
>>> 2,2,1,58
>>> 
>>>      [[alternative HTML version deleted]]
>>> 
>>> ______________________________________________
>>> R-help@ mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
>>> and provide commented, minimal, self-contained, reproducible code.
>>> 
>> 
>> 
>> Any of the following three works with me.
>> 
>> 
>> DF <- read.table(text="
>> Houseid,Personid,Tripid,taz
>> 1,1,1,4
>> 1,1,2,7
>> 2,1,1,96
>> 2,1,2,4
>> 2,1,3,2
>> 2,2,1,58
>> ", header=TRUE, sep=",")
>> 
>> DF
>> 
>> split(DF, DF[, 1:2], drop=TRUE)
>> split(DF, list(DF$Houseid, DF$Personid), drop=TRUE)
>> with(DF, split(DF, list(Houseid, Personid), drop=TRUE))
>> 
>> The argument 'drop' defaults to FALSE. Was that the problem?
>> 
>> Hope this helps,
>> 
>> Rui Barrada
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> 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.