search for: locid

I think I must be missing something obvious, but I'm having trouble getting a data transformation to work on groupings of data within a data frame (csss3) as defined by 2 factors (population, locid). The data are sorted by year within locid within population and I want to lag another variable (dbc), i.e, shift them down by 1 row replacing the first row with NA, within groups defined by locid nested within population. I thought I could do something using by(csss3,list(locid, population),...

...not dimensionally consistent with the data frame (data). So how do I go from the list output of tapply() to create a dimensionally consistent vector that can create the new variable in my original data frame? I've been trying to use a function like data$LAG1DBC <- tapply(data$DBC, data$LOCID, function(x) c(NA, x[-length(x)])) which creates a list of dimension much smaller than the nrows in data. And I've tried things like using as.data.frame.array() or as.data.frame.list() in front of tapply() and still have the same problem. I know this can't be that unusual of a data man...

Dear all, I have a big data matrix and I want to convert those data into weekly basis which means 7 days needs to be avaraged and aggregate a single value > dput(test) structure(list(locid = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1...

...immediate purpose they are not of interest now. Code (and i hope it does not come scrambled): ---------------------- > x3 <- read.csv("unique_veg_id.csv") ### columns in my data: > dimnames(x3)[[2]] [1] "LocatID" "Region" "Total" "LocID" "UTMX" "UTMY" "Class" "cat3_name" "EventID" "day_sampl" "uniqueID" > > x3_reg1 <- x3[x3$Region == "JELA_reg1",]> > ma1 <- ftable(xtabs(Total ~ uniqueID + cat3_name, data=x3_re...