R: Count frequency of values in nested list with sub-elements

One way with lapply(), unlist() and table():

count <- table(unlist(lapply(lst, unique)))
count
# Austria   Japan  Sweden 
#       5       1       2 


as.data.frame(count)
#      Var1 Freq
# 1 Austria    5
# 2   Japan    1
# 3  Sweden    2

Reproducible data (please provide yourself next time):

lst <- list(
  c('Austria', 'Austria', 'Austria'), 
  c("Austria", "Sweden"), 
  c("Austria", "Austria", "Sweden", "Sweden", "Sweden", "Sweden"), 
  c("Austria", "Austria", "Austria"), 
  c("Austria", "Japan")
)

Here is another base R option

colSums(
  do.call(
    rbind,
    lapply(
      lst,
      function(x) table(factor(x, levels = unique(unlist(lst)))) > 0
    )
  )
)

which gives

Austria  Sweden   Japan
      5       2       1

An option is also to stack into a two column data.frame, then take the unique and apply the table

table(unique(stack(setNames(lst, seq_along(lst))))$values)

#   Austria   Japan  Sweden 
#     5       1       2