[R] Build a dataframe row by row?

Remko Duursma remkoduursma at gmail.com
Wed Aug 5 02:28:20 CEST 2009


> Nice, but I need a few columns for the data.  Don't know how to do this with
> the method you suggest.

For each iteration, you make a vector of your 'data', in the example
it is a vector of length 3.
Each of the elements in this vector will become a column in the dataframe.

If that is not what you mean, can you give a specific example?

remko



> -N
>
> On 8/4/09 4:57 PM, Remko Duursma wrote:
>>
>> Hi Noah,
>>
>> there are a few ways to do this. Easiest is to keep adding an element
>> to a list, and then make it into a dataframe at the end, like this:
>>
>> resultlis<- list()
>> for(i in 1:10){
>>
>> # your calculations here
>> datavec<- runif(3)
>>
>> resultlis[[i]]<- datavec
>>
>> }
>> resultdfr<- as.data.frame(do.call("rbind", resultlis))
>>
>>
>> greetings,
>> Remko
>>
>> -------------------------------------------------
>> Remko Duursma
>> Post-Doctoral Fellow
>>
>> Centre for Plants and the Environment
>> University of Western Sydney
>> Hawkesbury Campus
>> Richmond NSW 2753
>>
>> Dept of Biological Science
>> Macquarie University
>> North Ryde NSW 2109
>> Australia
>>
>> Mobile: +61 (0)422 096908
>> www.remkoduursma.com
>>
>>
>>
>> On Wed, Aug 5, 2009 at 9:41 AM, Noah Silverman<noah at smartmediacorp.com>
>>  wrote:
>>
>>>
>>> Hi,
>>>
>>> Time for another of my "newbie" questions.
>>>
>>> Is it possible to build up a data.frame "row by row" as I go
>>>
>>> I'm going to be running a bunch of experiments (many in a loop) to test
>>> different things.  I'm using AUC as my main performance measure.
>>>
>>> My thought was to add a row to a data.frame for each iteration and then
>>> have
>>> a nice summary report at the end.
>>>
>>> I found how to import, export, and create from vectors.  I haven't been
>>> able
>>> to find how just make an empty one and add rows as I go.
>>>
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>>> http://www.R-project.org/posting-guide.html
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>>>
>>>
>




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