3
R - 是否有適用於可以爲矩陣的每個條目計算FUN的應用系列的函數?我有概率的n x m
矩陣M
- M[i, j] = p
是P(x = 1) = p
,P(x = 0) = 1 - p
,從M
樣,我可以用apply
,
apply(M, 1, function(x)(sample(0:1,length(x), replace = TRUE)))
,但我不知道這是否功能正常工作,因爲我認爲它應該是相當:R - 是否有適用於可以爲矩陣的每個條目計算FUN的應用系列的函數?
apply(M, 1, function(x)(sample(0:1,length(x), replace = TRUE, prob = x)))
,但第二個不起作用,除了有更簡單/更快的解決方案涉及其他apply
功能?
例如:
> M=matrix(runif(10*4),10,4)
> M
[,1] [,2] [,3] [,4]
[1,] 0.4497123 0.74045206 0.8112949 0.33122848
[2,] 0.5416048 0.35812976 0.3877630 0.01491928
[3,] 0.7164970 0.15793958 0.1822459 0.07017764
[4,] 0.7965967 0.85600843 0.3129818 0.25698186
[5,] 0.8553264 0.06880133 0.4516520 0.14231129
[6,] 0.8667404 0.49394338 0.1331386 0.37769487
[7,] 0.9446913 0.87368456 0.3680256 0.92143709
[8,] 0.4251636 0.69126643 0.5355501 0.45516271
[9,] 0.7483549 0.04289660 0.7817728 0.37752422
[10,] 0.0218563 0.91304663 0.4800049 0.19477370
> apply(M, 1, function(x)(sample(0:1,length(x), replace = TRUE, prob = x)))
Error in sample(0:1, length(x), replace = TRUE, prob = x) :
incorrect number of probabilities
> apply(M, 1, function(x)(sample(0:1,length(x), replace = TRUE)))
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] 1 0 0 1 0 0 1 1 0 0
[2,] 0 1 0 0 1 1 0 1 1 0
[3,] 0 1 0 1 1 0 1 1 1 1
[4,] 0 0 1 1 0 0 1 1 0 1
我使用的R用快5年了,我從來沒有聽說過「如果你想通過行採樣和列使用1:2」,太好了,謝謝 – Qbik 2013-03-25 22:06:33
@ Qbik它甚至在幫助中提到! – hadley 2013-03-26 13:32:37
@hadley indead ps。我喜歡RStudio – Qbik 2013-04-02 21:40:33