.... or use tapply(seq_len(nrow(d),d$id,...) or a wrapper version thereof (by, aggregate,...)
However, it would not surprise me if this does not help. I suspect that the problem is not what you think but in the code and context you omitted, as others have already noted. -- Bert On Thu, Nov 21, 2013 at 5:51 AM, Rainer M Krug <rai...@krugs.de> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > > > On 11/21/13, 12:34 , Jim Holtman wrote: >> you need to show the statement in context with the rest of the >> script. you need to tell us what you want to do, not how you want >> to do it. > > Agreed - a few details will result in guesses (see my guess below) > >> >> Sent from my iPad >> >> On Nov 20, 2013, at 15:16, Noah Silverman >> <noahsilver...@g.ucla.edu> wrote: >> >>> Hello, >>> >>> I have a fairly large data.frame. (About 150,000 rows of 100 >>> variables.) There are case IDs, and multiple entries for each ID, >>> with a date stamp. (i.e. records of peoples activity.) >>> >>> >>> I need to iterate over each person (record ID) in the data set, >>> and then process their data for each date. The processing part >>> is fast, the date part is fast. Locating the records is slow. >>> I've even tried using data.table, with ID set as the index, and >>> it is still slow. >>> >>> The line with the slow process (According to Rprof) is: >>> >>> >>> j <- which( d$id == person ) > > Possibly use > > d_by_id <- split(d, d$id) > > which splits the data.frame d into a listt, where each list represents > the data.frame of one id. > > But: Just a guess. > > Cheers, > > Rainer > >>> >>> (I then process all the records indexed by j, which seems fast >>> enough.) >>> >>> where d is my data.frame or data.table >>> >>> I thought that using the data.table indexing would speed things >>> up, but not in this case. >>> >>> Any ideas on how to speed this up? >>> >>> >>> Thanks! >>> >>> -- Noah Silverman, M.S., C.Phil UCLA Department of Statistics >>> 8117 Math Sciences Building Los Angeles, CA 90095 >>> >>> ______________________________________________ >>> R-help@r-project.org mailing list >>> https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the >>> posting guide http://www.R-project.org/posting-guide.html and >>> provide commented, minimal, self-contained, reproducible code. >> >> ______________________________________________ R-help@r-project.org >> mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do >> read the posting guide http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. >> > > - -- > Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation > Biology, UCT), Dipl. Phys. (Germany) > > Centre of Excellence for Invasion Biology > Stellenbosch University > South Africa > > Tel : +33 - (0)9 53 10 27 44 > Cell: +33 - (0)6 85 62 59 98 > Fax : +33 - (0)9 58 10 27 44 > > Fax (D): +49 - (0)3 21 21 25 22 44 > > email: rai...@krugs.de > > Skype: RMkrug > -----BEGIN PGP SIGNATURE----- > Version: GnuPG/MacGPG2 v2.0.22 (Darwin) > Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ > > iQEcBAEBAgAGBQJSjg/+AAoJENvXNx4PUvmC/kcH/3eaMvOTCAvA6ewwH/XJHH6X > B4BgstscvvJ3yArFeWqLIV0CEgk3da4c28+4Jk50vnltRVwUieFxKA1UK6Ef3gPl > pZUg9TaUNAeHPfkrxQSrYIa+hLWMZ1Ybe6GM1OlXnkc9ZBT9KS+rX3HFfr9rdyFI > Rv7SgrylUnpZIyiMeAzQS/FBzozV3G6mGu8FJ8YW5mHCqajI2alK3B3BBREzuLsL > ZMSuFDPTzxrE63O+uU6yFDibhz/4chKVz6CEF52WUgpgP+X4rW/DcLDrDfXxEvwM > ZDHcOZ8FJsuDl1lb1bdzSyS61KfzWls37i9VtOozqQwSFbaHbcdV16jHCPDzRPA= > =u5ol > -----END PGP SIGNATURE----- > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. -- Bert Gunter Genentech Nonclinical Biostatistics (650) 467-7374 ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
