Hi all,
I want to calculate the number of unique observations of "y" in each level
of "x" from my data frame "df".
this does the job but it is very slow for this big data frame (159503 rows,
11 columns).....
group.list <- split(df$y,df$x)
count <- function(x) length(unique(na.omit(x)))
sapply(group.list, count, USE.NAMES=TRUE)
I couldnt find the answer searching for "slow split" and "split time" on
help forum.
I am running R version 2.2.1, on a machine with 4gb of memory and I'm using
windows 2000.
thanks in advance,
Simon.
----- Original Message -----
From: "Wacek Kusnierczyk" <waclaw.marcin.kusnierc...@idi.ntnu.no>
To: "Gundala Viswanath" <gunda...@gmail.com>
Cc: "R help" <r-h...@stat.math.ethz.ch>
Sent: Friday, January 16, 2009 9:30 AM
Subject: Re: [R] Value Lookup from File without Slurping
you might try to iteratively read a limited number of line of lines in a
batch using readLines:
# filename, the name of your file
# n, the maximal count of lines to read in a batch
connection = file(filename, open="rt")
while (length(lines <- readLines(con=connection, n=n))) {
# do your stuff here
}
close(connection)
?file
?readLines
vQ
Gundala Viswanath wrote:
Dear all,
I have a repository file (let's call it repo.txt)
that contain two columns like this:
# tag value
AAA 0.2
AAT 0.3
AAC 0.02
AAG 0.02
ATA 0.3
ATT 0.7
Given another query vector
qr <- c("AAC", "ATT")
I would like to find the corresponding value for each query above,
yielding:
0.02
0.7
However, I want to avoid slurping whole repo.txt into an object (e.g.
hash).
Is there any ways to do that?
The reason I want to do that because repo.txt is very2 large size
(milions of lines,
with tag length > 30 bp), and my PC memory is too small to keep it.
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______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
