我有一个只有一列的txt文件
data=structure(list(V3 = c(1:120)), row.names = c(NA,120L), class = "data.frame")
我想这样计算平均数
first 12 rows >> first value
following 12 rows >> second value
etcs
我有一个只有一列的txt文件
data=structure(list(V3 = c(1:120)), row.names = c(NA,120L), class = "data.frame")
我想这样计算平均数
first 12 rows >> first value
following 12 rows >> second value
etcs
> colMeans(matrix(unlist(data), 12))
[1] 6.5 18.5 30.5 42.5 54.5 66.5 78.5 90.5 102.5 114.5
并以它的一些变体为基准
microbenchmark(
f1 = colMeans(matrix(unlist(data), 12)),
f2 = colMeans(matrix(data[[1L]], 12)),
f3 = colMeans(matrix(unlist(data, use.names = FALSE), 12)),
unit = "relative"
)
正在显示
Unit: relative
expr min lq mean median uq max neval
f1 4.166667 3.896226 3.729477 3.818182 3.652542 4.134752 100
f2 1.437500 1.433962 1.475840 1.436364 1.440678 3.886525 100
f3 1.000000 1.000000 1.000000 1.000000 1.000000 1.000000 100