search for: measurement1

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, d...

...e some example data. set.seed(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...