Dplyr在指定位置改变新列

另一个选择是 add_column 从 tibble

library(tibble)    
add_column(df, a1 = sum(a + 1), .after = "a")
#   a a1 b c d
#1 10 63 1 4 7
#2 20 63 2 5 8
#3 30 63 3 6 9

select_helper 函数可根据需要重新排列新创建的列:

library(dplyr)

## add a1 after a
df %>% 
    mutate(a1 = sum(a + 1)) %>%
    select(a, a1, everything())
#>    a a1 b c d
#> 1 10 63 1 4 7
#> 2 20 63 2 5 8
#> 3 30 63 3 6 9

## add a1 after c
df %>% 
    mutate(a1 = sum(a + 1)) %>%
    select(1:c, a1, everything())
#>    a b c a1 d
#> 1 10 1 4 63 7
#> 2 20 2 5 63 8
#> 3 30 3 6 63 9

这个 mutate 函数将始终在末尾添加新创建的列。但是,我们可以在 函数使用 select

library(dplyr)

df_1 <- df %>% 
  mutate(a1 = sum(a + 1)) %>%
  select(sort(names(.)))
df_1
#    a a1 b c d
# 1 10 63 1 4 7
# 2 20 63 2 5 8
# 3 30 63 3 6 9