[R] Merging files

[David Winsemius]

On Apr 27, 2010, at 4:23 PM, Alex Jameson wrote:

> David,
>
> merg12
>
> displays the files
> with this message at the bottom
>
> [reached getOption("max.print") -- omitted 321526 rows]]
>
> str(merg12) displays the following message
>
> 'data.frame' : 329218 obs. of 13 variables
>
> $ patientid:
> $ Name:
> $ Age:
>
> but no file is created in the folder mydata
>
> i would expect a file to be created, which is not happening

R is not SPSS. R does its work in memory and has particular functions  
to export or save data (which are two different processes). All this  
would be explained in any introductory text for R. I think you need to  
go back to the "Introduction to R" and the other introductory texts to  
get a better handle on the basics. I had checked it to see if merge  
were describe there and it was not, so I assumed you might have read  
it, but it seems not. You seem to have missed quite a few of its  
important lessons.

Perhaps unlike the SPSS equivalent (however it might be organized by  
IBM at the moment) the R-help mailing list is _not_ set up to be a  
tutoring facility. You are asked to study on your own the large amount  
of free introductory material, work through the examples ... on your  
own, ... and then and only then,  compose detailed questions with full  
code and complete example datasets. I did previously suggest that you  
read the Posting Guide. I now also repeat that suggestion. You might  
also read through the R-FAQ as well.

-- 
David.


>
> Thank you
>
> Alex
>
>
> On Tue, Apr 27, 2010 at 4:41 PM, David Winsemius <dwinsemius at comcast.net 
> >wrote:
>
>>
>> On Apr 27, 2010, at 4:23 PM, Alex Jameson wrote:
>>
>> Hi David,
>>>
>>> I have executed
>>>
>>> data1 <- read.table("c:\\mydata\\file1.txt")
>>> data2 <- read.table("c:\\mydata\\file2.txt")
>>>
>>> merg12 <- merge(data1, data2)
>>>
>>> but am not sure, if it has merged them,
>>> ideally, i would want a new file name for the merged data, based  
>>> on the
>>> identical IDs,
>>>
>>
>> That is what you should have gotten. what happens when you type
>>
>> merg12
>>
>> ??
>>
>> and i would need to eliminate some column names (fields) which are  
>> not
>>> required
>>>
>>
>> That can be don easily. Show us:
>>
>> str(merg12)
>>
>>
>> -- David.
>>
>>
>>>
>>> Alex
>>>
>>>
>>>
>>> On Tue, Apr 27, 2010 at 2:51 PM, David Winsemius <dwinsemius at comcast.net
>>>> wrote:
>>>
>>>
>>>> On Apr 27, 2010, at 1:19 PM, Alex Jameson wrote:
>>>>
>>>> This is a more detailed description of the problem,
>>>>
>>>>>
>>>>> I have written the following lines of code to read the files
>>>>>
>>>>> data1=("c:\\mydata\\file1.txt")
>>>>> data2=("c:\\mydata\\file2.txt")
>>>>>
>>>>>
>>>> NONONO. Read the manual again. Perhaps:
>>>>
>>>> data1 <- read.table("c:\\mydata\\file1.txt")
>>>> data2 <- read.table("c:\\mydata\\file2.txt")
>>>>
>>>>
>>>> file 1 has fields like patientID, Name which are common in file2,  
>>>> however
>>>>> not all fields are common
>>>>>
>>>>> i would like to create file3.txt with the merged data fields,
>>>>>
>>>>>
>>>> And what might happen happened when you tried:
>>>>
>>>> merg12 <- merge(data1, data2)
>>>>
>>>> ??? ...  by default it would merge on the field names (actually  
>>>> column
>>>> names in R-parlance) that were shared by the two dataframes.
>>>>
>>>> --
>>>> David
>>>>
>>>>
>>>>> i hope this is clear, and i thank everyone, who has responded so  
>>>>> far.
>>>>>
>>>>>
>>>>> Alex Jameson
>>>>> Student,
>>>>> University of Colorado
>>>>>
>>>>>     [[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<http://www.r-project.org/posting-guide.html 
>>>>> >
>>>>> <http://www.r-project.org/posting-guide.html>
>>>>>
>>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>>
>>>>>
>>>>
>>>>
>>>       [[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<http://www.r-project.org/posting-guide.html 
>>> >
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>> David Winsemius, MD
>> West Hartford, CT
>>
>>
>
> 	[[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.