dplyr group_by出错 [英] Error with dplyr group_by

问题描述

这是我的数据集

N  Pl

10, WO
20, EI
10, WO
20, WO
30, EI

我的预期输出是

N   Pl
10,  2
20,  1
30,  1 

所以，基本上，我正在计数每个值为N的pl的数字

So, basically, I am counting number of pl with each value at N

我正在尝试dplyr。我知道大概这也可以用aggregate（）完成，但我不知道该怎么做。所以在dplyr我正在运行这个声明并得到以下错误

I am trying dplyr. I know probably this can also be done with aggregate() but I am not sure how to do with that. So in dplyr I am running this statement and getting the following error

声明：

Diff %>% group_by(N) %>% summarise(pl=count(pl))

这里 Diff 是我的表名

Error in UseMethod("group_by_") : no applicable method for 'group_by_' applied to an object of class "c('integer', 'numeric')"

我不知道该怎么做任何帮助将不胜感激。另外我只有R的基本知识

I am not sure how to do that. Any help will be appreciated. Also I have only basic knowledge of R

推荐答案

也许你想要的输出是错误的，尝试：

Maybe your desired output is wrong, try:

library(dplyr)
df<-data.frame(N=c(10,20,10,20,30), Pl=c("WO","EI","WO","WO","EI"))
group <- group_by(df, N)
result <- as.data.frame(summarise(group, Pl = n_distinct(Pl)))
result

   N Pl
1 10  1
2 20  2
3 30  1

# the data.table way
library(data.table)
setDT(df)[, list(Pl=uniqueN(Pl)), by= N]

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