[R] reshaping a dataset for a network

[Marco Guerzoni]

thank you very much
I had managed with

df <- data.frame(a,b)
m <- lapply(split(df, df$a), function(x) x$b)
n <- max(sapply(m, length))
a <- t(sapply(m, function (x) c(x, rep(NA, n - length(x)))))

  but your solution is much more elegant.
best regards
Marco


Il 3/14/2012 1:54 PM, R. Michael Weylandt ha scritto:
> You can't have "empty" spots like that in an array. One choice would
> be to fill them with NAs:
>
> library(plyr)
> do.call(rbind.fill.matrix,lapply(split(b,a), t))
>
> Michael
>
> On Wed, Mar 14, 2012 at 4:01 AM, Marco Guerzoni<marco.guerzoni at unito.it>  wrote:
>> Thank you fro the reply.
>> I managed to arrive till here, then I would like to have it in matrix where
>> the $1 $2...$5 are the first column.
>>
>> Il 3/13/2012 8:15 PM, William Dunlap ha scritto:
>>
>>> Is the following what you want?
>>>    >    a<- c(1,2,3,4,4,4,5,5)
>>>    >    b<- c(11,7,4,9,8,3,12,4)
>>>    >    split(b, a)
>>>    $1
>>>    [1] 11
>>>
>>>    $2
>>>    [1] 7
>>>
>>>    $3
>>>    [1] 4
>>>
>>>    $4
>>>    [1] 9 8 3
>>>
>>>    $5
>>>    [1] 12  4
>>
>> Here I did
>>
>> c<- split(b, a)
>> d<- do.call(rbind,c)
>>
>> and I get
>>
>>   [,1] [,2] [,3]
>> 1   11   11   11
>> 2    7    7    7
>> 3    4    4    4
>> 4    9    8    3
>> 5   12    4   12
>>
>>
>> Instead of what I would like:
>>
>>   [,1] [,2] [,3]
>>
>> 1   11
>> 2    7
>> 3    4
>> 4    9    8    3
>> 5   12    4
>>
>> A solution could be rbind.fill , which does not seem to work with list.
>>
>>
>> thanks
>> Marco Guerzoni,
>> Department of Economics
>> University of Turin
>>
>>
>>
>>> Note that your df<-cbind(a,b) produces a matrix, not the data.frame
>>> that your df suggests you want.  Use df<-data.frame(a,b) to make
>>> a data.frame.  Then you could do with(df, split(a,b)) to operate on
>>> the a and b in the data.frame df.
>>>
>>> Bill Dunlap
>>> Spotfire, TIBCO Software
>>> wdunlap tibco.com
>>>
>>>
>>>> -----Original Message-----
>>>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
>>>> On Behalf
>>>> Of Marco Guerzoni
>>>> Sent: Tuesday, March 13, 2012 10:51 AM
>>>> To: r-help at r-project.org
>>>> Subject: [R] reshaping a dataset for a network
>>>>
>>>> dear all,
>>>> apologizes for bothering with a probably stupid question but I really
>>>> don' t know how to proceed.
>>>>
>>>> I have a dataset which look like df
>>>>
>>>> a<- c(1,2,3,4,4,4,5,5)
>>>> b<- c(11,7,4,9,8,3,12,4)
>>>> df<-cbind(a,b)
>>>>
>>>> I would like to have one which looks like this:
>>>>
>>>> a
>>>> 1 11
>>>> 2 7
>>>> 3 4
>>>> 4 9 8 3
>>>> 5 12 4
>>>>
>>>> a are vertex of a network, b the edges. In the data the lenght of a is
>>>> about 50000
>>>>
>>>> I read several posts about reshape, reshape2, split, ldply but I
>>>> couldn't manage to do it. The problem seems to be that the is not a real
>>>> panel.
>>>>
>>>> Any help would be really appreciated,
>>>> my best regards
>>>> Marco
>>>>
>>>> ______________________________________________
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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.
>>
>> ______________________________________________
>> 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.