使用tidyr中的unite：

library(tidyverse)
df %>%
  unite(EYE_ID, ID, EYE, remove = FALSE)

# A tibble: 5 × 3
  EYE_ID ID      EYE
  <chr>  <chr> <dbl>
1 GATE_1 GATE      1
2 GATE_2 GATE      2
3 GATE_3 GATE      3
4 GATE_4 GATE      4
5 GATE_5 GATE      5

甚至str_c

df %>% 
  mutate(EYE_ID = str_c(ID, EYE, sep = '_'))

# A tibble: 5 × 3
  ID      EYE EYE_ID
  <chr> <dbl> <chr> 
1 GATE      1 GATE_1
2 GATE      2 GATE_2
3 GATE      3 GATE_3
4 GATE      4 GATE_4
5 GATE      5 GATE_5

在R中，你可以用途：

transform(df, EYE_ID = paste(ID, EYE, sep = '_'))
    ID EYE EYE_ID
1 GATE   1 GATE_1
2 GATE   2 GATE_2
3 GATE   3 GATE_3
4 GATE   4 GATE_4
5 GATE   5 GATE_5