R: 以开头的所有列的总和

dplyr 有一个快速的答案:

library(dplyr)
df <- df %>% 
    mutate(
        m_col_sum = select(., starts_with("m")) %>% rowSums(),
        w_col_sum = select(., starts_with("w")) %>% rowSums()
    )

您可能需要指定 na.rm = TRUE 作为 rowSums() 。

另一种可能的解决方案:

library(dplyr)

df %>% 
  mutate(sum_m = across(starts_with("m")) %>% rowSums) %>% 
  mutate(sum_w = across(starts_with("w")) %>% rowSums)

#>         m_16 w_16 w_17 m_17 w_18 m_18 sum_m sum_w
#> values1    3    4    8    1   12    4     8    24
#> values2    8    0   12    1    3    2    11    15

# Vector containing the letters which target vectors' 
# names start with: names_start_with => character vector
names_start_with <- c("m", "w")

# Compute row-sums, column-bind vectors to data.frame: res => data.frame
res <- cbind(
  df,
  vapply(
    names_start_with, 
    function(x){
      rowSums(df[,startsWith(names(df), x)])
    }, 
    numeric(length(names_start_with))
  ),
  row.names = NULL
)

# Output data.frame to console: data.frame => stdout(console)
res