reproducible example to split dataset into intervals when sorted

split_subsets_example.R

# generate data, variables will be name X1 .... X8 
# dimension: 1200 rows, 7 cols
daten <- data.frame(matrix(rnorm(8400),ncol = 7))
# 8th col is just sequential id 1-1200
daten$id <- as.numeric(row.names(daten))


# assume data are sorted, 
# add another column that indicates
# the subset
x <- integer()
for(i in 1:10) x <- c(x,rep(i,120))
daten$subset <- x

# do the split trick
lapply(split(daten,factor(daten$subset)),
       summary)