计算数据框中的相同元素r

Question

r数据帧出现了另一个问题。

#starting position
from <- c("A","B","A","C")
to <- c("D","F","D","F")
number <- c(3,4,6,7)
data.frame(from,to,number)

如何计算两个相同“从 - 到”关系（从A到D）的数字？ 结果应该看起来像我的“结果”数据框。

#result
from <- c("A","B","C")
to <- c("D","F","F")
result <- c(9,4,7)
data.frame(from,to,result)

谢谢你们：）

Answer 1

您可以使用group_by对“from”和“to”进行分组，然后在汇总中使用sum来获取每个组的总数。

library(dplyr)
df %>% group_by(from,to) %>% summarise(result = sum(number))