How to look at differences between 2 columns in R

Question

I just need to write some code that will look at the difference between the "est_age" and "known_age" columns in my data set. Then I need to know what percentage were an exact match and what percentage were 1 different, 2 different, and 3 different

enter image description here

Fish_id Reader  est_age Known_age
1   BKF 5   7
2   BKF 7   16
3   BKF 4   5
4   BKF 12  12
5   BKF 6   10
6   BKF 5   6
7   BKF 8   12
8   BKF 5   5
9   BKF 7   7
10  BKF 6   7
11  BKF 8   8
12  BKF 5   7
13  BKF 5   7
14  BKF 5   14
15  BKF 6   6
16  BKF 6   7
17  BKF 6   6
18  BKF 6   5
19  BKF 15  18
20  BKF 8   7
21  BKF 7   4
22  BKF 8   12
23  BKF 7   8
24  BKF 9   7
25  BKF 5   8
26  BKF 11  23
27  BKF 6   5
28  BKF 4   4
29  BKF 6   7
30  BKF 7   12
31  BKF 6   6
32  BKF 5   5
33  BKF 5   8
34  BKF 11  10

Answer 1

I'm not quite sure what you're trying to accomplish. Remember the more precise your question is, the more helpful answer you get. Also try to provide an easy to use reproducible example (see r-package reprex).

You could have provided your data in a format like this:

df2 = 
structure(list(Fish_id = 1:34,
               Reader = rep("BKF", 34),
               est_age = c(5L, 7L, 4L, 12L, 6L, 5L, 8L, 5L, 7L, 6L, 8L, 5L, 5L, 5L, 6L, 6L, 6L, 6L, 15L, 8L, 7L, 8L, 7L, 9L, 5L, 11L, 6L, 4L, 6L, 7L, 6L, 5L, 5L, 11L),
               Known_age = c(7L, 16L, 5L, 12L, 10L, 6L, 12L, 5L, 7L, 7L, 8L, 7L, 7L, 14L, 6L, 7L, 6L, 5L, 18L, 7L, 4L, 12L, 8L, 7L, 8L, 23L, 5L, 4L, 7L, 12L, 6L, 5L, 8L, 10L)),
          row.names = c(NA, -34L), class = c("tbl_df", "tbl", "data.frame"))

The task is easily done with the data-wrangling package "dplyr":

library(dplyr)
df %>% 
  mutate(diff = abs(Known_age - est_age)) %>%    # calculate (absolute) differences
  count(diff) %>%     # count number of observations per difference
  mutate(n_rel = scales::percent(n / sum(n)))  # calculate percentage