[R] dataframe question

[Vadlamani, Satish {FLNA}]

David:
Thanks for the idea. Both the one that you suggested and the one that Bill Venables suggested are very good. Unfortunately, this statement is creating out of memory issues like below (system limitations).

When I had padded white space before the number, read.csv.sql is correctly treating it as a factor. I am going to take out the padding so that it treats it as numeric and then I can proceed with further steps.

Satish

Out of memory warning
Reached total allocation of 1535Mb: see help(memory.size)
34: In ans[[i]] <- tmp :
  Reached total allocation of 1535Mb: see help(memory.size)

>> Bill Venable's suggestion below

week_list <- paste("wk", 1:209, sep="")  
### no need for c(...)

for(week in week_list) 
	three_wk_out[[week]] <- as.numeric(three_wk_out[[week]]) 

### no need for '{...}'

Bill Venables
CSIRO/CMIS Cleveland Laboratories


-----Original Message-----
From: David Winsemius [mailto:dwinsemius at comcast.net] 
Sent: Sunday, February 07, 2010 8:51 PM
To: Vadlamani, Satish {FLNA}
Cc: r-help at r-project.org help
Subject: Re: [R] dataframe question


On Feb 7, 2010, at 8:14 PM, David Winsemius wrote:

>
> On Feb 7, 2010, at 7:51 PM, Vadlamani, Satish {FLNA} wrote:
>
>> Folks:
>> Good day. Please see the code below. three_wk_out is a dataframe  
>> with columns wk1 through wk209. I want to change the format of the  
>> columns. I am trying the code below but it does not work.  I need  
>> $week in the for loop interpreted as wk1, wk2, etc. Could you  
>> please help? Thanks.
>> Satish
>>
>> R code below
>> week_list <- paste("wk",c(1:209),sep="")
>
>
> Or more "functionally":
>
> three_wk_out <- as.data.frame( lapply(three_wk_out, some_function) )

Or if you wanted to just change the particular columns that matched  
the "wk" pattern:

idx <- grep("wk", names(three_wk_out))
three_wk_out[, idx ] <- apply( three_wk_out[, idx ], 2, as.numeric)


(I probably should have used apply( ___ , 2,  fn) in the prior effort  
rather than coercing a list back to a dataframe.)


>
> E.g.:
> >

>  a b c x
> 1 1 0 0 1
> 2 2 3 2 4
> 3 1 2 1 5
> 4 2 0 3 2
>
> > df <- as.data.frame(lapply(df, "^", 2))
> > df
>   a  b  c   x
> 1  1  0  0   1
> 2 16 81 16 256
> 3  1 16  1 625
> 4 16  0 81  16
>
>
>> for (week in week_list)
>> {
>>       three_wk_out$week <- as.numeric(three_wk_out$week)
>> }
>>
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>
> ______________________________________________
> 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.