R中是否有任何快速方法或内置函数来计算基于第三维的平均值?
例如我的数组是:
, , 1 [,1] [,2] [1,] 1 3 [2,] 2 4 , , 2 [,1] [,2] [1,] 11 13 [2,] 12 14 , , 3 [,1] [,2] [1,] 21 23 [2,] 22 24
我的输出是:
[,1] [,2] [1,] mean(1,11,21) mean(3,13,23) [2,] mean(2,12,22) mean(4,14,24)
Thanks!
?apply是您执行此类任务的朋友。
?apply
# Make the sample data j <- array(c(1:4, 11:14, 21:24), c(2,2,3)) # For each combination in the 1st and 2nd dimension # average over the values in the 3rd. apply(j, c(1,2), mean)