Question

我有一个10x3 NA矩阵，该矩阵用1-100之间的随机数填充一个随机行。我想选择另一个随机行（可以说不用替换）并填充它，而又不知道最初填充的是哪一行。我不确定如何进行第二选择。我想我将必须找到一种方法来将子集仅包含NA的行，然后随机选择。如果您需要详细信息，请告诉我。

myData <- matrix(data = NA,10,3)
random row selection.
myData[sample(1:10,size = 1,),] <- c(sample(1:100,size = 1,replace = TRUE),sample(1:100,size = 1,replace = TRUE),sample(1:100,size = 1,replace = TRUE))

不确定第二次随机选择

Answer 1

您实际上不需要单独存储子集。都可以在while循环中处理：

myData <- matrix(data = NA,10,3)

while(sum(is.na(myData))>0){ ## while there are NAs
  if (sum(is.na(myData)[,1])>1){ ## if it is not the last row (because the last row will need differetn approach being a vector, and not a matrix)
    myData[is.na(myData)[,1],][ ## from the subset of NAs whose first column (and hence all of it) is not NA
      sample(1:nrow(myData[ ## choose one randomly
        is.na(myData)[,1],] ),size = 1),] = sample(1:100,size = 3,replace = TRUE) ## substitute it by a random vector of the same length
  } else { ## for the last one
    myData[is.na(myData)[,1],]= sample(1:100,size = 3,replace = TRUE) 
  }

}

子集后随机选择行

1 个答案: