summarize groups into intervals using dplyr

Question

H, I have a data frame like this:

d <- data.frame(v1=seq(0,9.9,0.1),
            v2=rnorm(100),
            v3=rnorm(100))

> head(d)
   v1          v2         v3
1 0.0 -0.01431916 -0.5005415
2 0.1 -1.01575590  1.5307473
3 0.2  1.00081065 -0.1730830
4 0.3 -1.20697918  0.5105118
5 0.4 -2.16698578 -1.0120544
6 0.5  0.33886508  0.4797016

I now want a new data frame that summarizes all values in the intervals 0-0.99, 1-1.99, 2-2.99, 3-3.99,.... by the mean for example

like this

start end mean.v2 mean.v3
    0   1     0.2     0.1
    1   2     0.5     0.4

and so on

thanks

Update I should add that in my real data set the observations in each interval are of different lengths and they don't always start at zero or end at 10

Answer 1

here is one way using cut() as suggested by @akrun:

d %>% mutate( ints = cut(v1 ,breaks = 11)) %>% 
   group_by(ints) %>% 
   summarise( mean.v2 = mean(v2) , mean.v3 = mean(v3) )