See ?save . The ... arguments are the ***names*** of the objects, not
the objects
so you want save("d", ...whatever...) not save(d, ...whatever...) .
Also don't use attach and detach and read this about factors which applies
if your factor has many levels but can be ignored if not:
http://www.mail-archive.com/r-help@stat.math.ethz.ch/msg92970.html
On 8/21/07, Jessica Z <[EMAIL PROTECTED]> wrote:
> Hello List, i have been agonizing over this for days, any reply would be
> greatly appreciated!
>
> Situation:___________________________________
> My original dataset is a .csv dataset (w/ 2M records) with 4 variables:
> job_id (Primary key, won't be used for analysis, just used for join tables),
> sector_id (categorical variable, for 19 industry sectors),
> sqft (con't variable for square footage),
> building_type (categorical, for 2 building types)
> some values of sqft were inputed wrong, so i'd like to set sqft<1 to "NA"
> and then use aregImpute() to impute those NAs.
>
> Problem: the origianl dataset(.csv format) is too large. though i could read
> that dataset into R, i could not get aregImpute() run even i set the memory
> limit to 3G ! (yes, i did the switch in windows to reach 3G rather than 2G)
>
> Goal: try to find a way to slim down my dataset so as to get aregImpute()
> running.
>
> What i did:________________________________
> i searched in the archive, and found someone said, as R tends to inflate
> memory, it is a good idea to first read the original dataset into R--> then
> save it as a more compact binary file using save() --> and then reload the
> compact binary file back into R using load(). this way would reduce the
> memory allocation.
>
> HOWEVER, after i saved my original dataset into a compact binary file using
> save(), and used "load("filename.Rdata") to reload the new compact data
> format into R, I could not figure out how to retrive all my variables!!! R
> shows the new dataset is not a list, nor a matrix, or a dataframe, but just a
> character with length 1 !!! and there is no way i could do attach().
>
> i generated a 1K-row subset out of my original dataset to illustrate my
> problem (does anyone know how to get my four variables back from this
> "compact binary" new dataset? what did i do wrong?):
>
> > data <- read.table (file.choose(),header=T,sep=",")
> > summary(data)
> job_id sector_id sqft building_type
> Min. : 1.0 Min. : 6.000 Min. : 0.00 Min. :1.000
> 1st Qu.: 250.8 1st Qu.: 6.000 1st Qu.: 3.00 1st Qu.:2.000
> Median : 500.5 Median :11.000 Median : 4.00 Median :2.000
> Mean : 500.5 Mean : 9.455 Mean : 12.49 Mean :1.996
> 3rd Qu.: 750.3 3rd Qu.:11.000 3rd Qu.: 4.00 3rd Qu.:2.000
> Max. :1000.0 Max. :12.000 Max. :192.00 Max. :2.000
> >
> > attach(data)
> > sqft[sqft<1] <- NA
> > sector.f <- as.factor(sector_id)
> > building_type.f <- as.factor (building_type)
> > d <- data.frame(job_id,sector.f,sqft, building_type.f)
> > summary (d)
> job_id sector.f sqft building_type.f
> Min. : 1.0 6 :340 Min. : 3.00 1: 4
> 1st Qu.: 250.8 11:505 1st Qu.: 4.00 2:996
> Median : 500.5 12:155 Median : 4.00
> Mean : 500.5 Mean : 14.16
> 3rd Qu.: 750.3 3rd Qu.: 17.00
> Max. :1000.0 Max. :192.00
> NA's :118.00
> > save (d, file="compact_d.Rdata", ascii=FALSE)
> >
> > newdata <- load ("compact_d.Rdata")
> >
> > summary(newdata)
> Length Class Mode
> 1 character character
> > attach(newdata)
> Error in attach(newdata) : file 'd' not found
> > is.data.frame (newdata)
> [1] FALSE
> > is.list (newdata)
> [1] FALSE
> > is.matrix (newdata)
> [1] FALSE
> >
> _________________________________
> btw, i also tried to just save (into compact binary) and reload (the new
> compact binary data format) (as i could do the "NA" stuff in sql anyhow).
> however, i still got stucked at the same spot:
> > data <- read.table (file.choose(),header=T,sep=",")
> > summary(data)
> job_id sector_id sqft building_type
> Min. : 1.0 Min. : 6.000 Min. : 0.00 Min. :1.000
> 1st Qu.: 250.8 1st Qu.: 6.000 1st Qu.: 3.00 1st Qu.:2.000
> Median : 500.5 Median :11.000 Median : 4.00 Median :2.000
> Mean : 500.5 Mean : 9.455 Mean : 12.49 Mean :1.996
> 3rd Qu.: 750.3 3rd Qu.:11.000 3rd Qu.: 4.00 3rd Qu.:2.000
> Max. :1000.0 Max. :12.000 Max. :192.00 Max. :2.000
> > save (data, file="compact_data.Rdata", ascii=FALSE)
> > newdata <- load ("compact_data.Rdata")
> > summary(newdata)
> Length Class Mode
> 1 character character
> > attach(newdata)
> Error: restore file may be empty -- no data loaded
> In addition: Warning message:
> file 'data' has magic number ''
> Use of save versions prior to 2 is deprecated
> > is.data.frame (newdata)
> [1] FALSE
> > is.list (newdata)
> [1] FALSE
> > is.matrix (newdata)
> [1] FALSE
> >
>
>
>
>
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