如何在R列中总结观察结果？

我有一个df1：

Number State
42     AK
65     AK
31     TN
34     TN
12     MO
3      AK
41     MO
53     TN
23     AK

我想总结一下缔约国的意见：

要查看：

State Obs
AK    4
TN    3
MO    2

您可以使用dplyr软件包：

汇总功能将只保留分组变量状态和汇总变量Obs

数据：

---

或df1%>%countState@IceCreamToucan，这是更简单的解决方案，谢谢。然而，如果出于某种原因计数变量必须命名为Obs是不够的

library(dplyr)

df1 %>%
#grouping rows by State
  group_by(State) %>%
#using 'n()' to count number of observations for each State
  summarize(Obs = n())

df1 <- data.frame(Number = c(42, 65, 31, 34, 12, 3, 41, 53, 23),
                  State = c("AK", "AK", "TN", "TN", "MO", "AK", "MO", "TN", "AK"))