On Feb 7, 2010, at 11:15 PM, Vadlamani, Satish {FLNA} wrote:

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.

Idea: Write the dataframe and all other useful data to a csv or tab delimited file. Save all other useful data as well. Exit without saving the workspace. Restart and read data in with correct format using colClasses argument.

three_wk_out <- read.csv(file= "somename.csv", colClasses = rep("numeric", 209) )

Of course if it's that big, you may have problems doing anything useful with it in the space you have available. Details of your machine would be helpful, especially if you are using one of the Windows variant and have 4 GB of physical memory. There is information about this condition in the R-Win FAQ.

--
David.



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:dwinsem...@comcast.net]
Sent: Sunday, February 07, 2010 8:51 PM
To: Vadlamani, Satish {FLNA}
Cc: r-help@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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