How to create a consecutive group number

Question

I have a data frame (all_data) in which I have a list of sites (1... to n) and their scores e.g.

  site  score
     1    10
     1    11  
              


        

Answer 1

You can turn site into a factor and then return the numeric or integer values of that factor:

dat <- data.frame(site = rep(c(1,4,8), each = 3), score = runif(9))
dat$number <- as.integer(factor(dat$site))
dat

  site     score number
1    1 0.5305773      1
2    1 0.9367732      1
3    1 0.1831554      1
4    4 0.4068128      2
5    4 0.3438962      2
6    4 0.8123883      2
7    8 0.9122846      3
8    8 0.2949260      3
9    8 0.6771526      3