search for: measurement2

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2009 Jul 15
0
strategy to iterate over repeated measures/longitudinal data
...ed(1) wide_data <- data.frame( id=c(1:10), predictor1 = sample(c("a","b"),10,replace=TRUE), predictor2 = sample(c("a","b"),10,replace=TRUE), predictor3 = sample(c("a","b"),10,replace=TRUE), measurement1=rnorm(10), measurement2=rnorm(10)) head(wide_data) id predictor1 predictor2 predictor3 measurement1 measurement2 1 1 a a b -0.04493361 -0.05612874 2 2 a a a -0.01619026 -0.15579551 3 3 b b b 0.94383621 -1.47075238 4 4...
2010 Sep 24
2
Data manipulation in R
...measurement types (fortunately only one value per measurement type per day). I want to know how I can separate this into multiple columns by measurement type averaged over the range of dates available. The output would have a single averaged measurement value per site. Site, Measurement 1, measurement2, measurement3, etc. I have been reading it in as a matrix as.matrix(read.table("myfile.txt", headers=TRUE)), but I don't quite know what to do with it afterward. Thanks [[alternative HTML version deleted]]
2007 Oct 26
2
how do i find the annual maximun within several years?
dear kind helper, i would like to know how to find the annual maximun for a table that basicly looks like this: date time measurement1 measurement2 measurement3 mm/dd/yyyy hh:mm:ss m1 m2 m3 there are about 9000 measurements for each year, which makes it quite large... i already tried to subset all rows for a year, to find the maximum within these choosen rows, y <- grep(yyyy,table[,1],value=TRUE) df <-table[with(table, date == y), ]...