[R] transforming a dataset for association analysis RESHAPE2

[Ista Zahn]

Hi Ajay,
I'm not sure what the problem is, and I don't think your description
is enough to reproduce it. This works fine for me


library(reshape2)

dat <- read.table(textConnection('Subject   Item Score
"Subject 1" "Item 1"     1
"Subject 1" "Item 2"     0
"Subject 1" "Item 3"     1
"Subject 2" "Item 1"     1
"Subject 2" "Item 2"     1
"Subject 2" "Item 3"     0'), header=TRUE)
closeAllConnections()

acast(dat, Subject~Item)

sessionInfo()
R version 2.12.0 (2010-10-15)
Platform: i686-pc-linux-gnu (32-bit)

locale:
 [1] LC_CTYPE=en_US.utf8       LC_NUMERIC=C
 [3] LC_TIME=en_US.utf8        LC_COLLATE=en_US.utf8
 [5] LC_MONETARY=C             LC_MESSAGES=en_US.utf8
 [7] LC_PAPER=en_US.utf8       LC_NAME=C
 [9] LC_ADDRESS=C              LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.utf8 LC_IDENTIFICATION=C

attached base packages:
[1] grid      stats     graphics  grDevices utils     datasets  methods
[8] base

other attached packages:
[1] reshape2_1.0  ggplot2_0.8.8 proto_0.3-8   reshape_0.8.3 plyr_1.2.1

loaded via a namespace (and not attached):
[1] stringr_0.4  tools_2.12.0

-Ista

On Mon, Nov 1, 2010 at 10:39 AM, Ajay Ohri <ohri2007 at gmail.com> wrote:
> I get the following message when using the reshape2 package line
>
>> tDat.m<- melt(Dataset)
> Using Item, Subject as id variables
>> tDatCast<- acast(tDat.m,Subject~Item)
> Aggregation function missing: defaulting to length
>
>
> Note Problem Statement-
>
> convert dataframe
>
>
> Subject   Item Score
> 1 Subject 1 Item 1     1
> 2 Subject 1 Item 2     0
> 3 Subject 1 Item 3     1
> 4 Subject 2 Item 1     1
> 5 Subject 2 Item 2     1
> 6 Subject 2 Item 3     0
>
> to
>
>
>  Subject Item 1 Item 2 Item 3 Item 4
> 1 Subject 1      1      0      1      1
> 5 Subject 2      1      1      0      0
>
> Note- when I tried using the "wide" method the resultant vector went out of
> memory- its a dataset appox 100,000 lines
>
>
>
> Websites-
> http://decisionstats.com
> http://dudeofdata.com
>
>
> Linkedin- www.linkedin.com/in/ajayohri
>
>
>
>
> On Sat, Oct 30, 2010 at 5:41 PM, Rainer Hurling <rhurlin at gwdg.de> wrote:
>
>> On 30.10.2010 13:50 (UTC+1), Santosh Srinivas wrote:
>>
>>> A more usable problem input would definitely help ... use dput to send a
>>> reproducible sample to the group
>>>
>>> Think the below should solve your problem
>>>
>>>  read.csv("Book1.csv")
>>>>
>>>     Subject   Item Score
>>> 1 Subject 1 Item 1     1
>>> 2 Subject 1 Item 2     0
>>> 3 Subject 1 Item 3     1
>>> 4 Subject 2 Item 1     1
>>> 5 Subject 2 Item 2     1
>>> 6 Subject 2 Item 3     0
>>>
>>>  library("reshape2")
>>>> tDat.m<- melt(tDat)
>>>>
>>>
>>>  tDatCast<- acast(tDat.m,Subject~Item)
>>>> tDatCast
>>>>
>>>           Item 1 Item 2 Item 3
>>> Subject 1      1      0      1
>>> Subject 2      1      1      0
>>>
>>
>>
>> # Or without using package reshape2, only function reshape from stats:
>>
>> df <- data.frame(Subject=
>>                   c("Subject 1","Subject 1","Subject 1","Subject 1",
>>                     "Subject 2","Subject 2","Subject 2","Subject 2"),
>>                 Item   =
>>                   c("Item 1","Item 2","Item 3","Item 4",
>>                     "Item 1","Item 2","Item 3","Item 4"),
>>                 Score  = c(1,0,1,1,1,1,0,0))
>>
>> df.wide <- reshape(df, idvar="Subject", timevar="Item", direction="wide")
>> names(df.wide) <- c("Subject",unique(as.character(df$Item)))
>>
>> df.wide
>>    Subject Item 1 Item 2 Item 3 Item 4
>> 1 Subject 1      1      0      1      1
>> 5 Subject 2      1      1      0      0
>>
>>
>>
>>  -----Original Message-----
>>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
>>> On
>>> Behalf Of Ajay Ohri
>>> Sent: 30 October 2010 16:27
>>> To: Rhelp
>>> Subject: [R] transforming a dataset for association analysis
>>>
>>> Hi
>>>
>>> I would like to transform  a data frame like
>>>
>>> Subject    Item   Score
>>> Subject 1 Item 1 1
>>> Subject 1 Item 2 0
>>> Subject 1 Item 3 1
>>> Subject 2 Item 1 1
>>> Subject 2 Item 2 1
>>> Subject 2 Item 3 0
>>> ....
>>> *to *
>>>
>>> Subject      Item1   Item2   Item3 .....Item N
>>> Subject1       1          0       1
>>> Subject2       1          1        0
>>> ........
>>> SubjectP..
>>>
>>> Apologize for the simple nature of my query but I am stuck. How can I do
>>> this transformation?
>>>
>>> Regards
>>>
>>> Ajay
>>>
>>>
>>>
>>> Websites-
>>> http://decisionstats.com
>>> http://dudeofdata.com
>>>
>>>
>>> Linkedin- www.linkedin.com/in/ajayohri
>>>
>>>
>>>
>>>
>>> On Sat, Oct 30, 2010 at 2:39 PM, Alaios<alaios at yahoo.com>  wrote:
>>>
>>>  Hello everyone.
>>>> I have written quite a big function that at the end correctly returns the
>>>> values
>>>> I want. I found a rare exception that I want to cover also. The easier
>>>> for
>>>> me
>>>> would be to write something like that
>>>>
>>>>
>>>> function(){
>>>>
>>>>  if (rare exception happened)
>>>>      return that value
>>>>
>>>>  # The comes the code for normal execution
>>>>  # ...
>>>>  # ...
>>>>  return value # Normal values to return
>>>>
>>>> }
>>>>
>>>>
>>>> Would that be feasible with R or two returns statements are not accepted?
>>>>
>>>> Regards
>>>> Alex
>>>>
>>>
>
>        [[alternative HTML version deleted]]
>
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>



-- 
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org