如何在R中的数据帧中找到值的总和？

Question

我有数据框：

x=c("a","a","b","b","b","c","c","d","e","f","f")
y=c(2,3,6,2,5,6,2,1,4,3,2)
df=data.frame(x,y)

如何创建一个新的日期框架，列出x列中的字母，然后给出y列中值的总和？这就是我想要创建的内容：

   x y
1  a 5
2  b 13
3  c 11
4  d 2
5  e 4
6  f 5   

Answer 1

这很容易用dplyr，

如果你没有它

install.packages("dplyr")

library(dplyr)

x=c("a","a","b","b","b","c","c","d","e","f","f")
y=c(2,3,6,2,5,6,2,1,4,3,2)
df=data.frame(x,y)

df <-df %>% group_by(x) %>% summarise(y = sum(y))