如何查找R中某個數據幀內的值的總和？

Question

我有數據幀：

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) 

如何創建一個新的日期框列出從x列的字母，然後給出了值從y列的總和？這是我想創造什麼：

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

Answer 1

這容易dplyr，

如果沒有它

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))