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.