Push up and tighten Dataframe. General solution

Question

I want to push up (metaphorically) the dataframe in ordner to get rid of the spaces (NA-Values)

My Data:

> dput(df1)
structure(list(ID = c("CN1         


        

Answer 1

do.call(rbind,
        lapply(split(df1, df1$ID), function(a)
            data.frame(ID = a$ID[1], lapply(a[-1], sum, na.rm = TRUE))))
#           ID       v1    v2  v2.1
#CN1-1   CN1-1 0.376730 0.732 0.357
#CN1-10 CN1-10 1.019972 0.000 0.816
#CN1-11 CN1-11 0.515152 0.748 0.519
#CN1-12 CN1-12 0.375139 0.466 0.206
#CN1-13 CN1-13 0.508125 0.570 0.464