如何通过在R数据框中使用两个因子列来查找累积和？

2024-04-22 02:59:04 21

通常，累积总和是针对单个变量计算的，在某些情况下，是基于单个类别变量的，在极少数情况下，我们想要对两个类别变量进行计算。如果要为两个类别变量找到它，则需要将数据帧转换为data.table对象，并使用cumsum函数定义具有累加和的列。

示例

请看以下数据帧：

> set.seed(1361)
> Factor1<-as.factor(sample(LETTERS[1:4],20,replace=TRUE))
> Factor2<-as.factor(sample(c("T1","T2","T3","T4"),20,replace=TRUE))
> Response<-rpois(20,5)
> df1<-data.frame(Factor1,Factor2,Response)
> df1

输出结果

Factor1 Factor2 Response
1 A T2 9
2 B T1 8
3 B T1 2
4 A T2 3
5 B T1 7
6 B T2 7
7 D T2 7
8 D T4 7
9 C T4 6
10 B T1 6
11 A T2 4
12 A T2 4
13 C T1 7
14 B T3 1
15 A T3 6
16 D T1 3
17 B T1 8
18 D T4 5
19 D T2 3
20 C T1 4

加载data.table包：

> library(data.table)

将数据帧df1转换为data.table对象：

> dt1<-data.table(df1)

基于因子1和因子2创建具有累积总和的列CumulativeSums：

示例

> dt1[,CumulativeSums:=cumsum(Response),by=list(Factor1,Factor2)]
> dt1

输出结果

Factor1 Factor2 Response CumulativeSums
1: A T2 9 9
2: B T1 8 8
3: B T1 2 10
4: A T2 3 12
5: B T1 7 17
6: B T2 7 7
7: D T2 7 7
8: D T4 7 7
9: C T4 6 6
10: B T1 6 23
11: A T2 4 16
12: A T2 4 20
13: C T1 7 7
14: B T3 1 1
15: A T3 6 6
16: D T1 3 3
17: B T1 8 31
18: D T4 5 12
19: D T2 3 10
20: C T1 4 11

让我们看另一个例子：

示例

> G1<-as.factor(sample(c("Hot","Cold"),20,replace=TRUE))
> G2<-as.factor(sample(c("Low","Medium","Large"),20,replace=TRUE))
> Y<-sample(1:100,20)
> df2<-data.frame(G1,G2,Y)
> df2

输出结果

G1 G2 Y
1 Hot Medium 60
2 Cold Low 94
3 Hot Low 22
4 Cold Medium 90
5 Hot Medium 16
6 Hot Large 32
7 Cold Low 44
8 Hot Low 73
9 Hot Medium 99
10 Hot Medium 68
11 Cold Medium 41
12 Cold Large 77
13 Cold Large 48
14 Cold Medium 20
15 Cold Medium 18
16 Cold Low 12
17 Cold Low 30
18 Hot Low 23
19 Cold Medium 26
20 Cold Medium 4

示例

> dt2<-data.table(df2)
> dt2[,CumulativeSums:=cumsum(Y),by=list(G1,G2)]
> dt2

输出结果

G1 G2 Y CumulativeSums
1: Hot Medium 60 60
2: Cold Low 94 94
3: Hot Low 22 22
4: Cold Medium 90 90
5: Hot Medium 16 76
6: Hot Large 32 32
7: Cold Low 44 138
8: Hot Low 73 95
9: Hot Medium 99 175
10: Hot Medium 68 243
11: Cold Medium 41 131
12: Cold Large 77 77
13: Cold Large 48 125
14: Cold Medium 20 151
15: Cold Medium 18 169
16: Cold Low 12 150
17: Cold Low 30 180
18: Hot Low 23 118
19: Cold Medium 26 195
20: Cold Medium 4 199

如何通过在R数据框中使用两个因子列来查找累积和？

示例

示例

示例

示例

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