[R] Populating then sorting a matrix and/or data.frame

Noah Silverman noah at smartmediacorp.com
Thu Nov 11 08:40:41 CET 2010


That was a typo.

It should have read:
results[results$one < 100,]

It does still fail.

There is ONE column that is text.  So my guess is that R is seeing that 
and assuming that the entire data.frame should be factors.

-N

On 11/10/10 11:16 PM, Michael Bedward wrote:
> Hello Noah,
>
> If you set these names...
>> names(results)<- c("one", "two", "three")
> this won't work...
>> results[results$c<  100,]
> because you don't have a column called "c" (unless that's just a typo
> in your post).
>
>> I tried making it a data.frame with
>> foo<- data.frame(results)
>>
>> But that converted all the numeric values to factors!!!
> Not sure what's going on there. If 'results' is a numeric matrix you
> should get a data.frame with numeric cols since under the hood this is
> just calling the as.data.frame function.
>
> Michael
>
>
>
>
>
> On 11 November 2010 16:02, Noah Silverman<noah at smartmediacorp.com>  wrote:
>> Hi,
>>
>> I have a process in R that produces a lot of output.  My plan was to build
>> up a matrix or data.frame "row by row", so that I'll have a nice object with
>> all the resulting data.
>>
>> I started with:
>> results<- matrix(ncol=3)
>> names(results)<- c("one", "two", "three")
>>
>> Then, when looping through the data:
>> results<- rbind(results, c(a,b,c))
>>
>> This seems to work fine. BUT, my problem arises when I want to filter, sort,
>> etc.
>>
>> I tried (thinking like a data.frame):
>> results[results$c<  100,]
>>
>> But that fails.
>>
>> I tried making it a data.frame with
>> foo<- data.frame(results)
>>
>> But that converted all the numeric values to factors!!!  Which causes a
>> whole mess of problems.
>>
>> Any ideas??
>>
>> -N
>>
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