r - 如何用加权平均分组汇总数据？

Question

与

xa=aggregate(x$avg,by=list(x$value),FUN=weighted.mean,w=x$weight)

给我一​​个错误

Error in weighted.mean.default(X[[1L]], ...) :    'x' and 'w' must
have the same length

但是

weighted.mean(x$avg,w=x$weight);

工作正常。

Answer 1

按照 old R thread 上的建议，您可以使用 by 代替:

wt <- c(5,  5,  4,  1)/15
x <- c(3.7,3.3,3.5,2.8)
xx <- data.frame(avg=x, value=gl(2,2), weight=wt)
by(xx, xx$value, function(x) weighted.mean(x$avg, x$weight))