如何計算R中具有不同行值的列中2個單元格的總和

Question

以下是我的數據框：

   Col A   ColB   Col C   Col D   ColE
1  BBB     2100   2200    2300    2300
2  AAA     1750   1750    1800    1900

3  DDD     140      140     140     140
4  CCC     90       90      90      90

產量

    Col A   ColB   Col C   Col D   ColE
1  BBB     2100   2200    2300    2300
2  AAA     1750   1750    1800    1900

3  DDD     140      140     140     140
4  CCC     90       90      90      90

5  RRR    2,190.00   2,290.00    2,390.00    2,390.00 

我需要使用“ DDD”來計算“ BBB”的（總和）值

Answer 1

如果它是第一列， colSums %in% column1的值對行進行子集，刪除該列並獲得colSums

rbind(df1, c("Col A" = "RRR", 
        as.list(colSums(df1[df1$"Col A" %in% c("BBB", "DDD"),-1]))))
#   Col A ColB Col C Col D ColE
#1   BBB 2100  2200  2300 2300
#2   AAA 1750  1750  1800 1900     
#3   DDD  140   140   140  140
#4   CCC   90    90    90   90
#5   RRR 2240  2340  2440 2440

數據

df1 <- structure(list(`Col A` = c("BBB", "AAA", "DDD", "CCC"), ColB = c(2100L, 
 1750L, 140L, 90L), `Col C` = c(2200L, 1750L, 140L, 90L), `Col D` = c(2300L, 
 1800L, 140L, 90L), ColE = c(2300L, 1900L, 140L, 90L)),
  class = "data.frame", row.names = c("1", 

“ 2”，“ 3”，“ 4”））