在 R 中对字符数组求平均

Question

我有两个字符子数组如下：

, , 1

    [,1] [,2] [,3] [,4] [,5]
[1,] "5"  "3"  "1"  "1"  "5" 
[2,] "4"  "1"  "1"  "1"  "3" 
[3,] "5"  "5"  "4"  "5"  "1" 
[4,] "5"  "5"  "1"  "3"  "5" 
[5,] "3"  "4"  "1"  "4"  "5" 
[6,] "2"  "5"  "4"  "5"  "2" 
[7,] "2"  "5"  "5"  "4"  "2" 
[8,] "5"  "5"  "2"  "2"  "2" 
[9,] "2"  "5"  "4"  "5"  "4" 
[10,] "2"  "2"  "5"  "2"  "1" 

, , 2

    [,1] [,2] [,3] [,4] [,5]
[1,] "2"  "2"  "2"  "4"  "5" 
[2,] "3"  "1"  "2"  "1"  "4" 
[3,] "5"  "2"  "3"  "4"  "4" 
[4,] "3"  "3"  "4"  "5"  "3" 
[5,] "2"  "1"  "5"  "1"  "3" 
[6,] "5"  "5"  "2"  "5"  "4" 
[7,] "1"  "5"  "1"  "3"  "4" 
[8,] "1"  "5"  "3"  "3"  "5" 
[9,] "4"  "5"  "1"  "1"  "2" 
[10,] "5"  "1"  "2"  "3"  "5" 

现在我编写了一个 R 例程，用于从其中一个数组（,,1 或 ,,2）中随机抽取一行。

但我想做的是从两个子数组中随机采样并取列平均值。我可以在不先将字符转换为数值的情况下完成此操作吗？

因此，如果在 ,,1 和 ,,2 中都对第 1 行进行采样，则列平均值（适当舍入）将是（未在 R 中完成）

  "(5+2)/2", "(3+2)/2", "(1+2)/2", "(1+4)/2", "(5+5)/2"
= "4", "3", "2", "3", "5"

我的（部分）例程从 ONE 数组中随机采样一行如下。我想为两个数组修改它。

for(k in specs){
    for(j in 1:perms){
        for(i in 1:K){
            ind.index <- sample(specs, size = k, replace = FALSE) 
            hap.plot <- pop[sample(1:nrow(pop), size = 1, replace = TRUE), ind.index, sample(i, size = 1, replace = TRUE)]
            HAC.mat[j, k, i] <- length(unique(hap.plot))
    }
  }
}

非常感谢任何帮助。

如果需要更多说明，请告诉我。

Answer 1

我们可以使用apply

i1 <- sample(seq_len(dim(ar1)[1]), 2)
apply(ar1[i1,,], c(1, 2), FUN = function(x) mean(as.numeric(x)))

或者通过第三维循环使用rowMeans

rowMeans(apply(ar1[i1,,], 3, FUN = function(x) as.numeric(x)))

数据

set.seed(24)
ar1 <- array(as.character(sample(1:5, 10*5*2, replace = TRUE)), dim = c(10, 5, 2))

Answer 2

测试数据

mat <- array(as.character(1:40), c(15, 5, 2))

分别从每个样本中随机抽样并获得平均值。

n_row <- dim(mat)[1]
s_rows <- sample(1:n_row, 2, replace = TRUE)

unlist(lapply(mat[s_rows[1],, 1], as.numeric))/2 + 
  unlist(lapply(mat[s_rows[2],, 2], as.numeric))/2