Question

我有一个字频数据帧，例如：

df <- data.frame(
    Predictor = c("for","of","as","for","for","as","of","of","as","for"),
    ToPredict = c("sure","course","much","him","keeps","far","them","this","an","petes"),
    Freq = c(53,32,21,17,13,5,3,2,2,1))

我想计算一个新列，它是每个ToPredict构成每个预测变量的比例。

因此，在上面的示例中，此新列的值为：

df$Props = c(0.631,0.865,0.75,0.202,0.155,0.179,0.081,0.054,0.071,0.012)

目前，我有一个总和的数据框：

sums <- aggregate(df$Freq, by=list(Category=df$Predictor), FUN=sum)

我尝试过：

df$Props <- with(df, Freq/sums$x[which(sums$Category == Predictor)])

显然，这不起作用。但我不知道会发生什么。非常感谢任何帮助。

Answer 1

Per thelatemail：

with(df, ave(Freq, Predictor, FUN=prop.table))

Answer 2

a=aggregate(df$Freq, by=list(df$Pred), FUN=sum)
a1=a[,2]
names(a1)=as.character(a[,1])
df$Props=df$Freq/a1[df$Pred]

从数据框中逐组计算比例

2 个答案: