First, in R there is no need to declare the dimensions of your objects
before they are populated so couldn't you reduce some run time by not
going through the double data.frame step ?
> df<- data.frame()
> df
data frame with 0 columns and 0 rows
> for(i in 1:100) for(j in 1:3) df[i,j]<- runif(1)
>
Row)
for (j in colNums) {
length(data[[j]]) <- curSize
}
}
for(j in colNums) {
data[[j]][i] <- i + j/10
}
}
names(data) <- colNames
data.frame(data)
}
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibc
On Tue, Feb 14, 2012 at 2:31 PM, William Dunlap wrote:
> If you must repeatedly append rows to a data.frame,
> try making the dataset you are filling in a bunch
> of independent vectors, perhaps in a new environment
> to keep things organized.
One complication is I don't know the names of the c
d
52.193.81 54.69
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
> -Original Message-
> From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On
> Behalf Of Peter Meilstrup
> Sent: Tuesday, February 14, 2012 1:47 PM
> To: r-help@r-project.
I'm reading a file and using the file to populate a data frame. The way the
file is laid out, I need to fill in the data frame one row at a time.
When I start reading my file, I don't know how many rows I will need. It's
on the order of a million.
Being mindful of the time expense of reallocation
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