I hope this reproduceble example helps understand what I'm trying to do. This is the function:
# Make Data Frame for video actions between given times for user X DataVideoActionT <- function (userX, Time1, Time2, Time3){ #Get data for user X videoActionsX<-subset(videoLectureActions, username==userX) #Time1 = before first attempt videoActionsX_T1<-subset(videoActionsX, eventTimestamp<Time1) #Time2 = before best attemp videoActionsX_T2<-subset(videoActionsX, eventTimestamp<Time2 & eventTimestamp>Time1) #Time3= before last attemp videoActionsX_T3<-subset(videoActionsX, eventTimestamp<Time3 & eventTimestamp>Time1) error1 = sum(videoActionsX_T1$type==" error ") pause1 = sum(videoActionsX_T1$type==" pause ") play1 = sum(videoActionsX_T1$type==" play ") ratechange1 = sum(videoActionsX_T1$type==" ratechange ") seeked1 = sum(videoActionsX_T1$type==" seeked ") stalled1 = sum(videoActionsX_T1$type==" stalled ") error2 = sum(videoActionsX_T2$type==" error ") pause2 = sum(videoActionsX_T2$type==" pause ") play2 = sum(videoActionsX_T2$type==" play ") ratechange2 = sum(videoActionsX_T2$type==" ratechange ") seeked2 = sum(videoActionsX_T2$type==" seeked ") stalled2 = sum(videoActionsX_T2$type==" stalled ") error3 = sum(videoActionsX_T3$type==" error ") pause3 = sum(videoActionsX_T3$type==" pause ") play3 = sum(videoActionsX_T3$type==" play ") ratechange3 = sum(videoActionsX_T3$type==" ratechange ") seeked3 = sum(videoActionsX_T3$type==" seeked ") stalled3 = sum(videoActionsX_T3$type==" stalled ") data<-data.frame(anon_ID=userX, error1 = error1, pause1 = pause1, play1 = play1, ratechange1 = ratechange1, seeked1=seeked1, stalled1=stalled1, error2 = error2, pause2 = pause2, play2 = play2, ratechange2 = ratechange2, seeked2 =seeked2, stalled2 = stalled2, error3 = error3, pause3 = pause3, play3 = play3, ratechange3 = ratechange3, seeked3 = seeked3, stalled3 = stalled3) return(data) } This is the videoActionsX dataframe: structure(list(username = c("exampleID1", "exampleID1", "exampleID1", "exampleID2", "exampleID2", "exampleID2", "exampleID3", "exampleID3", "exampleID3", "exampleID3"), currentTime = c("103.701247", "103.701247", "107.543877", "107.543877", "116.456507", "116.456507", "119.987188", "177.816693", "183.417124", "183.417124"), playbackRate = c("null", "null", "null", "null", "null", "null", "null", "null", "null", "null"), pause = c("true", "false", "true", "false", "true", "false", "true", "false", "true", "false"), error = c("null", "null", "null", "null", "null", "null", "null", "null", "null", "null"), networkState = c("1", "1", "1", "1", "1", "1", "1", "1", "1", "1"), readyState = c("4", "4", "4", "4", "4", "4", "4", "4", "4", "4"), lectureID = c("exampleLectureID1", "exampleLectureID1", "exampleLectureID1", "exampleLectureID1", "exampleLectureID1", "exampleLectureID1", "exampleLectureID1", "exampleLectureID1", "exampleLectureID1", "exampleLectureID1"), eventTimestamp = c("2013-03-04 18:51:49", "2013-03-04 18:51:50", "2013-03-04 18:51:54", "2013-03-04 18:51:56", "2013-03-04 18:52:05", "2013-03-04 18:52:07", "2013-03-04 18:52:11", "2013-03-04 18:59:17", "2013-03-04 18:59:23", "2013-03-04 18:59:31" ), initTimestamp = c("2013-03-04 18:44:15", "2013-03-04 18:44:15", "2013-03-04 18:44:15", "2013-03-04 18:44:15", "2013-03-04 18:44:15", "2013-03-04 18:44:15", "2013-03-04 18:44:15", "2013-03-04 18:44:15", "2013-03-04 18:44:15", "2013-03-04 18:44:15"), type = c(" pause ", " play ", " pause ", " play ", " pause ", " play ", " pause ", " play ", " pause ", " play "), prevTime = c("103.701247 ", "103.701247 ", "107.543877 ", "107.543877 ", "116.456507 ", "116.456507 ", "119.987188 ", "177.816693 ", "183.417124 ", "183.417124 ")), .Names = c("username", "currentTime", "playbackRate", "pause", "error", "networkState", "readyState", "lectureID", "eventTimestamp", "initTimestamp", "type", "prevTime"), row.names = c(1L, 2L, 5L, 6L, 17L, 21L, 28L, 936L, 957L, 988L), class = "data.frame") But with over 2000 observation. And this is the other data frame structure(list(anon_ID = c("exampleID1", "exampleID2", "exampleID3" ), maxGrade = c(10, 5, 10), firstGrade = c(10, 5, 8), lastGrade = c(10, 5, 10), total_submissions = c(1L, 1L, 3L), Time1 = structure(c(1361993741, 1362356090, 1362357401), class = c("POSIXct", "POSIXt"), tzone = ""), TimeM = structure(c(1361993741, 1362356090, 1362492744), class = c("POSIXct", "POSIXt"), tzone = ""), TimeL = structure(c(1361993741, 1362356090, 1362492744), class = c("POSIXct", "POSIXt"), tzone = "")), .Names = c("anon_ID", "maxGrade", "firstGrade", "lastGrade", "total_submissions", "Time1", "TimeM", "TimeL"), row.names = c(NA, 3L), class = "data.frame") But with a lot more observations. What I want to do is to call function (userX, Time1, Time2, Time3) for all the user in the second data frame where Time1=Time1, Time2=TimeM, Time3=TimeL I hope that is more clear. Thanks a lot for all the help! On Sun, Sep 1, 2013 at 11:33 AM, Bert Gunter <gunter.ber...@gene.com> wrote: > Oh, another possibility is ?mapply, which I should have pointed out in my > previous reply. Sorry. > > -- Bert > > > On Sun, Sep 1, 2013 at 8:30 AM, Bert Gunter <bgun...@gene.com> wrote: > >> Rui et.al.: >> >> But apply will not work if the data frame has columns of different >> classes/types, as appears to be the case here. Viz, from ?apply: >> >> "If X is not an array but an object of a class with a non-null >> dim<http://127.0.0.1:12824/help/library/base/help/dim> >> value (such as a data frame),apply attempts to coerce it to an array via >> as.matrix if it is two-dimensional (e.g., a data frame) or via as.array. >> " >> >> Simply looping by rows (via for() ) appears to be the simplest and >> probably fastest solution. There are other ways via tapply() and friends, >> but these are also essentially loops and are likely to incur some >> additional overhead. >> >> All assuming I understand what the OP has requested, of course. >> >> Cheers, >> >> Bert >> >> >> On Sun, Sep 1, 2013 at 7:31 AM, Rui Barradas <ruipbarra...@sapo.pt>wrote: >> >>> Hello, >>> >>> Maybe you need apply, not lapply. It seems you want to apply() a >>> function to the first dimension of your data.frame, something like >>> >>> apply(dat, 1, fun) #apply by rows >>> >>> >>> Hope this helps, >>> >>> Rui Barradas >>> >>> Em 01-09-2013 15:00, Ignacio Martinez escreveu: >>> >>>> I have a Data Frame that contains, between other things, the following >>>> fields: userX, Time1, Time2, Time3. The number of observations is 2000. >>>> >>>> I have a function that has as inputs userX, Time1, Time2, Time3 and >>>> return >>>> a data frame with 1 observation and 19 variables. >>>> >>>> I want to apply that function to all the observations of the first data >>>> frame to make a new data frame with 2000 observations and 19 variables. >>>> >>>> I thought about using lapply, but if I understand correctly, it only >>>> takes >>>> one variable. >>>> >>>> Can somebody point me in the right direction? >>>> >>>> Thanks! >>>> >>>> [[alternative HTML version deleted]] >>>> >>>> ______________________________**________________ >>>> R-help@r-project.org mailing list >>>> https://stat.ethz.ch/mailman/**listinfo/r-help<https://stat.ethz.ch/mailman/listinfo/r-help> >>>> PLEASE do read the posting guide http://www.R-project.org/** >>>> posting-guide.html <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<https://stat.ethz.ch/mailman/listinfo/r-help> >>> PLEASE do read the posting guide http://www.R-project.org/** >>> posting-guide.html <http://www.R-project.org/posting-guide.html> >>> and provide commented, minimal, self-contained, reproducible code. >>> >> >> >> >> -- >> >> Bert Gunter >> Genentech Nonclinical Biostatistics >> >> Internal Contact Info: >> Phone: 467-7374 >> Website: >> >> http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm >> >> > > > > -- > > Bert Gunter > Genentech Nonclinical Biostatistics > > Internal Contact Info: > Phone: 467-7374 > Website: > > http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm > > [[alternative HTML version deleted]] ______________________________________________ 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.