transform a complicate list to a data frame - r

Question

Sorry if this question has been formulated before, but I am totalyy new and I tried what was suggested in other post here with no result. For example I tried:
do.call("rbind", lapply(MET1, as.data.frame))
But it said:
Error in as.data.frame.default(X[[i]], ...) : cannot coerce class
""mixEM"" to a data.frame
I have this list of lists (MET1) with 7 elements (showed below) and I want to transform it into a simplified data frame. Each row of the data frame needs to be one of the elements and I only need the information of lambda, mu and sigma. So basically something like this:
LAMBDA1 LAMBDA2 MU1 MU2 SIGMA1 SIGMA2
0102-A451 0.822 0.178 1711 10850 249 14986
0102-A453 0.813 0.187 1491 4031 108 6877
...
My list of lists is:
str(MET1)
List of 7
$ 0102-A451:List of 9
..$ x : num [1:178] 2088 1579 1638 1507 1862 ...
..$ lambda : num [1:2] 0.822 0.178
..$ mu : num [1:2] 1711 10850
..$ sigma : num [1:2] 249 14986
..$ loglik : num -1440
..$ posterior : num [1:178, 1:2] 0.991 0.997 0.997 0.996 0.996 ...
.. ..- attr(*, "dimnames")=List of 2
.. .. ..$ : NULL
.. .. ..$ : chr [1:2] "comp.1" "comp.2"
..$ all.loglik: num [1:16] -1703 -1518 -1472 -1450 -1442 ...
..$ restarts : num 0
..$ ft : chr "normalmixEM"
..- attr(*, "class")= chr "mixEM"
$ 0102-A453:List of 9
..$ x : num [1:663] 1414 1506 1399 1423 1421 ...
..$ lambda : num [1:2] 0.813 0.187
..$ mu : num [1:2] 1491 4031
..$ sigma : num [1:2] 108 6877
..$ loglik : num -4847
..$ posterior : num [1:663, 1:2] 0.996 0.997 0.995 0.996 0.996 ...
.. ..- attr(*, "dimnames")=List of 2
.. .. ..$ : NULL
.. .. ..$ : chr [1:2] "comp.1" "comp.2"
..$ all.loglik: num [1:29] -5760 -4983 -4883 -4861 -4853 ...
..$ restarts : num 0
..$ ft : chr "normalmixEM"
..- attr(*, "class")= chr "mixEM"
...

Answer 1

Here's a tidyverse solution, first we extract the relevant subsets of the lists and convert them to tibble (adding also row numbers). Then we bind the tibbles and do standard tidyr gymnastics :
MET1 %>%
map_dfr(~as_tibble(.x[c("lambda","mu","sigma")]) %>% rownames_to_column,
.id="id") %>%
gather(,,-rowname,-id) %>%
unite(key,key,rowname) %>%
spread(key,value)
# # A tibble: 2 x 7
# id lambda_1 lambda_2 mu_1 mu_2 sigma_1 sigma_2
# * <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
# 1 1 0.822 0.178 1711 10850 249 14986
# 2 2 0.813 0.187 1491 4031 108 6877
data:
MET1 <- list(
list(lambda = c(0.822, 0.178),
mu = c(1711, 10850),
sigma = c(249, 14986),
something_else="whatever"),
list(lambda = c(0.813, 0.187),
mu = c(1491, 4031),
sigma = c(108, 6877),
something_else="whatever")
)

Answer 2

Overview
Use lapply() to transform each list within MET1 into a wide data frame. Then, use rbind()
within do.call() to collapse all the lists within MET1 into one data frame. Thank you #Moody_Mudskipper for creating the reproducible data.
# load data
MET1 <-
list(
`0102-A451` = list(
lambda = c(0.822, 0.178),
mu = c(1711, 10850),
sigma = c(249, 14986),
something_else = "whatever"
)
, `0102-A453` = list(
lambda = c(0.813, 0.187),
mu = c(1491, 4031),
sigma = c(108, 6877),
something_else = "whatever"
)
)
# Transfrom MET1
# so that each list is a wide data frame
MET1 <-
lapply(
X = MET1
, FUN = function( i )
data.frame(
LAMBDA_1 = i[["lambda"]][1]
, LAMBDA_2 = i[["lambda"]][2]
, MU_1 = i[["mu"]][1]
, MU_2 = i[["mu"]][2]
, SIGMA_1 = i[["sigma"]][1]
, SIGMA_2 = i[["sigma"]][2]
)
)
# now transfrom MET1
# into one data frame
# one row for each data frame within MET1
MET1 <-
do.call(
what = "rbind"
, args = MET1
)
# view results
MET1
# LAMBDA_1 LAMBDA_2 MU_1 MU_2 SIGMA_1
# 0102-A451 0.822 0.178 1711 10850 249
# 0102-A453 0.813 0.187 1491 4031 108
# SIGMA_2
# 0102-A451 14986
# 0102-A453 6877
# end of script #