如何在R中按组对变量求和？

在本文中，让我们讨论如何在 R 编程语言中按组查找变量的总和。

使用中的数据集：

表格1

预期输出：

按类别分组

方法

创建数据框
将值设置为所需参数
传递给正在使用的函数
显示数据框

方法一：使用聚合函数

在这种方法中，我们将借助聚合函数按组求和。聚合函数将数据拆分为子集，计算每个子集的汇总统计信息，并以方便的形式返回结果。

句法：

aggregate(x = dataset_Name , by = group_list, FUN = any_function) # Basic R syntax of aggregate function

编程需要懂一点英语

例子：

R

GFG <- data.frame(
   Category  = c ("A","B","C","B","C","A","C","A","B"), 
   Frequency= c(9,5,0,2,7,8,1,3,7)
)
  
aggregate(x= GFG$Frequency,              
         by = list(GFG$Category),        
         FUN = sum)

R

library("dplyr")                             
GFG <- data.frame(
   Category  = c ("A","B","C","B","C","A","C","A","B"), 
   Frequency= c(9,5,0,2,7,8,1,3,7)
)
GFG%>%                                         
 group_by(Category) %>%                        
 summarise_at(vars(Frequency),                 
              list(name = sum))

输出：

方法二：使用dplyr

dplyr 是一个包，它提供了一组工具来有效地操作 R 中的数据集

Methods in dplyr package

mutate() adds new variables that are functions of existing variables
select() picks variables based on their names.
filter() picks cases based on their values.
summarise() reduces multiple values down to a single summary.
arrange() changes the ordering of the rows.

编程需要懂一点英语

在使用这个包之前，你必须安装它

程序：

电阻

library("dplyr")                             
GFG <- data.frame(
   Category  = c ("A","B","C","B","C","A","C","A","B"), 
   Frequency= c(9,5,0,2,7,8,1,3,7)
)
GFG%>%                                         
 group_by(Category) %>%                        
 summarise_at(vars(Frequency),                 
              list(name = sum))

输出：