如何查找一个 R 数据帧的组别汇总统计数据?
为了比较不同的组,我们需要每个组的汇总统计数据。它帮助我们观察组之间的差异。汇总统计数据提供最小值、第一四分位数、中值、第三四分位数以及最大值。因此,我们可以比较组的每个值。为了查找 R 数据帧的组别汇总统计数据,我们可以使用 tapply 函数。
示例
考虑以下数据帧 −
> set.seed(99) > x1<-sample(1:100,50,replace=TRUE) > x2<-rep(c("G1","G2","G3","G4","G5"),times=10) > df<-data.frame(x1,x2) > head(df,20) x1 x2 1 48 G1 2 33 G2 3 44 G3 4 22 G4 5 99 G5 6 62 G1 7 98 G2 8 32 G3 9 13 G4 10 20 G5 11 100 G1 12 31 G2 13 68 G3 14 9 G4 15 82 G5 16 88 G1 17 30 G2 18 86 G3 19 84 G4 20 32 G5
找到每组的 x1 汇总统计数据 −
> tapply(df$x1, df$x2, summary) $G1 Min. 1st Qu. Median Mean 3rd Qu. Max. 14.0 55.0 72.0 67.8 86.5 100.0 $G2 Min. 1st Qu. Median Mean 3rd Qu. Max. 4.0 31.5 60.5 52.4 69.5 98.0 $G3 Min. 1st Qu. Median Mean 3rd Qu. Max. 14.0 33.5 41.0 46.9 64.5 86.0 $G4 Min. 1st Qu. Median Mean 3rd Qu. Max. 9.00 23.75 53.00 53.30 82.75 97.00 $G5 Min. 1st Qu. Median Mean 3rd Qu. Max. 7.00 31.25 32.00 42.40 44.75 99.00
再来看一个示例 −
> y1<-rep(c(letters[1:5]),times=5) > y2<-rep(c(14,25,13,12,41,52,44,28,17,30),times=c(2,5,3,3,1,5,1,2,2,1)) > df_y<-data.frame(y1,y2) > head(df_y,20) y1 y2 1 a 14 2 b 14 3 c 25 4 d 25 5 e 25 6 a 25 7 b 25 8 c 13 9 d 13 10 e 13 11 a 12 12 b 12 13 c 12 14 d 41 15 e 52 16 a 52 17 b 52 18 c 52 19 d 52 20 e 44 > tapply(df_y$y2, df_y$y1, summary) $a Min. 1st Qu. Median Mean 3rd Qu. Max. 12.0 14.0 25.0 26.2 28.0 52.0 $b Min. 1st Qu. Median Mean 3rd Qu. Max. 12.0 14.0 25.0 26.2 28.0 52.0 $c Min. 1st Qu. Median Mean 3rd Qu. Max. 12.0 13.0 17.0 23.8 25.0 52.0 $d Min. 1st Qu. Median Mean 3rd Qu. Max. 13.0 17.0 25.0 29.6 41.0 52.0 $e Min. 1st Qu. Median Mean 3rd Qu. Max. 13.0 25.0 30.0 32.8 44.0 52.0
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