Question

我正在尝试将列表列表转换为组成矩阵。该代码有效，但我确定有更好的方法。感谢您的帮助。

#create list of lists
theta <- list()

for(k in 1:10){
theta[[k]] <- list(
  alpha=rnorm(n=3,mean=0,sd=2),
  mu=rnorm(n=3,mean=0,sd=2),
  sd=rnorm(n=3,mean=0,sd=2))
}

#extract parts
alpha_out <- theta[[1]]$alpha
mu_out <- theta[[1]]$mu
sd_out <- theta[[1]]$sd
for(k in 2:length(theta)){
  alpha_out <- rbind(alpha_out,theta[[k]]$alpha)
  mu_out <- rbind(mu_out,theta[[k]]$mu)
  sd_out <- rbind(sd_out,theta[[k]]$sd)
}

Answer 1

您可以像这样使用sapply：

alpha_out <- t(sapply(theta, function(x) {x$alpha}))
alpha_out <- t(sapply(theta, `[[`, 1))

Answer 2

如果您想将alpha，mu和sd分开，我们可以使用tranpose中的purrr

library(purrr)
transpose(theta) %>% map(dplyr::bind_cols)

#$alpha
# A tibble: 3 x 10
#      V1    V2     V3     V4     V5      V6     V7    V8     V9    V10
#   <dbl> <dbl>  <dbl>  <dbl>  <dbl>   <dbl>  <dbl> <dbl>  <dbl>  <dbl>
#1  1.65  0.295  0.145 -0.207 -0.857 -1.20   -0.665 4.19   1.20  -2.60 
#2 -0.578 3.12  -2.14   0.798  0.946  0.0866 -0.217 1.86   0.147 -0.610
#3  2.42  0.804  1.72   2.14  -1.85   0.604   1.84  0.968 -1.51  -1.09 

#$mu
# A tibble: 3 x 10
#       V1     V2     V3     V4    V5    V6     V7    V8      V9    V10
#    <dbl>  <dbl>  <dbl>  <dbl> <dbl> <dbl>  <dbl> <dbl>   <dbl>  <dbl>
#1 -0.0152 -2.34  -1.26   1.04   1.70 1.22  -3.01   1.80 -1.43    0.548
#2 -4.59   -0.917 -0.164 -0.384  1.09 0.259  0.265  2.55 -0.0560 -3.18 
#3  0.616   1.02  -0.707  3.86  -1.73 2.15  -2.91  -2.30 -1.65   -1.43 

#$sd
# A tibble: 3 x 10
#      V1     V2    V3    V4     V5     V6     V7      V8    V9    V10
#   <dbl>  <dbl> <dbl> <dbl>  <dbl>  <dbl>  <dbl>   <dbl> <dbl>  <dbl>
#1 -3.03  -0.705  1.10 -2.29  2.95   1.91   0.548 -2.08   -2.72 -2.93 
#2  2.59   3.91  -1.05  2.76  3.41   1.25  -0.291 -2.30   -1.48  2.70 
#3  0.242 -0.860  3.31 -4.19 -0.639 -0.720 -0.983  0.0544  2.00  0.939

将列表列表转换为矩阵

2 个答案: