r - Get range of adjacent rows with the same value -

i have dataframe below. first column positions , last level. want output range of rows same number in adjacent rows. '2' should ignored. can help

the input:

 1          3 10000       3 20000       3 30000       1 40000       2 50000       2 60000       2 70000       3 80000       1 90000       1  output  1-  2999 3 3000-3999 1 7000-7999 3 8000-9999 1 

here's method using chaning functions of dplyr. here's sample data

dd <- structure(list(pos = c(1l, 10000l, 20000l, 30000l, 40000l, 50000l,    60000l, 70000l, 80000l, 90000l), level = c(3l, 3l, 3l, 1l, 2l,    2l, 2l, 3l, 1l, 1l)), .names = c("pos", "level"), class = "data.frame",   row.names = c(na, -10l)) dd <- dd[order(dd$pos), ]  #make sure sorted position 

if difference next pos 10000, can do

library(dplyr) dd %>% arrange(pos) %>%      mutate(run=cumsum(c(0,diff(level))!=0)) %>%      subset(level!=2) %>%      group_by(run) %>%     summarise(level=max(level), start=min(pos), end=max(pos)+9999) %>%     select(-run)  #   level start   end # 1     3     1 29999 # 2     1 30000 39999 # 3     3 70000 79999 # 4     1 80000 99999 

otherwise

dd %>% arrange(pos) %>%      mutate(run=cumsum(c(0,diff(level))!=0), nextpos=lead(pos)) %>%      subset(level!=2) %>%      group_by(run) %>%     summarise(level=max(level), start=min(pos), end=max(nextpos)-1) %>%     select(-run)  #   level start   end # 1     3     1 29999 # 2     1 30000 39999 # 3     3 70000 79999 # 4     1 80000    na 

can calculate distance next group last group.