I've used lists (generic vectors) for this, with integer storage mode. Then I can easily manipulate them in R, they don't take too much room, and C code to traverse them (e.g. find connected components) is fast.
Did you have a need for a data frame? That seems like it might be painful to manipulate. I read the text file with readLines. Reid Huntsinger -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Aaron J. Mackey Sent: Tuesday, April 27, 2004 5:10 PM To: [EMAIL PROTECTED] Subject: [R] reading a "sparse" matrix into R I have a 47k x 47k adjacency matrix that is very sparse (at most 30 entries per row); my textual representation therefore is simply an adjacency list of connections between nodes for each row, e.g. node connections A B C D E B A C D C A E D A E A F F E G H I'd like to import this into a dataframe of node/connection (character/vector-of-characters) pairs. I've experimented with scan, but haven't been able to coax it to work. I can also "hack" it with strsplit() myself, but I thought there might be a more elegant way. Thanks, -Aaron ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
