如何在R数据框中查找因子列的频数表?
如果我们在R数据框中拥有因子列,那么我们想要查找所有因子列中每个因子水平的频率。这可以使用`sapply`函数和`table`函数来完成。例如,如果我们有一个名为`df`的数据框包含一些因子列,那么可以使用命令`sapply(df,table)`创建因子列的频数表。
示例1
考虑以下数据框:
> x1<-sample(LETTERS[1:4],20,replace=TRUE) > x2<-sample(letters[1:4],20,replace=TRUE) > df1<-data.frame(x1,x2) > df1
输出
x1 x2 1 D a 2 D b 3 D c 4 D b 5 D c 6 C a 7 C a 8 B a 9 A a 10 C c 11 D a 12 D b 13 D b 14 A c 15 C b 16 D a 17 A b 18 A b 19 B c 20 C b
在df1中查找因子列的频数表:
> sapply(df1,table) $x1
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输出
A B C D 4 2 5 9
示例
$x2
输出
a b c 7 8 5
示例2
> y1<-sample(c("India","Russia","UK"),20,replace=TRUE) > y2<-sample(c("Male","Female"),20,replace=TRUE) > df2<-data.frame(y1,y2) > df2
输出
y1 y2 1 India Male 2 UK Female 3 Russia Male 4 India Female 5 India Female 6 India Male 7 UK Female 8 Russia Male 9 UK Male 10 India Male 11 Russia Male 12 UK Male 13 UK Female 14 India Female 15 India Female 16 Russia Female 17 Russia Female 18 Russia Female 19 India Female 20 India Female
在df2中查找因子列的频数表:
> sapply(df2,table) $y1
输出
India Russia UK 9 6 5
示例
$y2
输出
Female Male 12 8
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