Create an id based on column value in R

Question

I am working on a two columns dataset in R representing response values ("Response") of different samples belonging to different groups ("Group") and I want to create a third ID column to identify each sample with a number from 1 to [..] (there is not the same number of sample in each group). Here is just a few lines as an example: Example

Thanks for your help.

Does this answer your question? [Numbering rows within groups in a data frame](https://stackoverflow.com/questions/12925063/numbering-rows-within-groups-in-a-data-frame) — user438383, Jun 02 '21 at 10:43

score 0 · Accepted Answer · answered Jun 02 '21 at 10:44

0

try

library(tidyverse)
your_data %>%
  group_by(Group)%>%
  mutate(ID = 1:n())

answered Jun 02 '21 at 10:44

L Smeets

888
4
17

score 0 · Answer 2 · answered Jun 02 '21 at 10:54

We could use cur_group_id

library(dplyr)
df %>% 
  group_by(Group) %>% 
  mutate(new_id = cur_group_id())

Output:

  Group Response    Id new_id
  <chr>    <dbl> <dbl>  <int>
1 A          1.5     1      1
2 A          3.4     2      1
3 A          2.3     3      1
4 A          1.8     4      1
5 B          1.9     1      2
6 B          1.4     2      2
7 C          2.7     1      3
8 C          2.3     2      3
9 C          3.2     3      3

Create an id based on column value in R

2 Answers2