2013-03-11 58 views

回答

7

試試這個:

set.seed(45) # just for reproducibility 
NCols <- 100 
NRows <- 100 
myMat <- matrix(runif(NCols*NRows), ncol=NCols) 

mat_minus_mean <- abs(myMat - mean(myMat)) 
idx <- which(mat_minus_mean == min(mat_minus_mean), arr.ind = TRUE) 
#  row col 
# [1,] 5 33 

> myMat[idx] 
# [1] 0.5# mean(myMat) is 0.5012474 
+0

我會改變的東西更像是'M < - which.min(ABS(myMat - 均值(myMat))); arrayInd(m,dim(myMat))'。速度應該更快,而且你不必擔心浮點運算是否會造成混亂。 – 2013-03-11 20:07:47

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